Turn nested generic FactoryBean type into resolved Class for fallback match

See gh-29385

Author: jhoeller

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

@@ -110,6 +110,11 @@ protected boolean checkGenericTypeMatch(BeanDefinitionHolder bdHolder, Dependenc
 					Class<?> typeToBeMatched = dependencyType.resolve();
 					if (typeToBeMatched != null && !FactoryBean.class.isAssignableFrom(typeToBeMatched)) {
 						targetType = targetType.getGeneric();
+						if (descriptor.fallbackMatchAllowed()) {
+							// Matching the Class-based type determination for FactoryBean
+							// objects in the lazy-determination getType code path below.
+							targetType = ResolvableType.forClass(targetType.resolve());
+						}
 					}
 				}
 			}

spring-context/src/test/java/org/springframework/context/annotation/AnnotationConfigApplicationContextTests.java

@@ -16,9 +16,7 @@
 
 package org.springframework.context.annotation;
 
-import java.util.Collections;
 import java.util.Map;
-import java.util.Set;
 import java.util.regex.Pattern;
 
 import org.junit.jupiter.api.Test;
@@ -400,44 +398,66 @@ void individualBeanWithFactoryBeanSupplierAndTargetType() {
 	void individualBeanWithFactoryBeanTypeAsTargetType() {
 		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
 		RootBeanDefinition bd1 = new RootBeanDefinition();
-		bd1.setBeanClass(SetFactoryBean.class);
-		bd1.setTargetType(ResolvableType.forClassWithGenerics(FactoryBean.class, ResolvableType.forClassWithGenerics(Set.class, String.class)));
+		bd1.setBeanClass(GenericHolderFactoryBean.class);
+		bd1.setTargetType(ResolvableType.forClassWithGenerics(FactoryBean.class, ResolvableType.forClassWithGenerics(GenericHolder.class, String.class)));
 		bd1.setLazyInit(true);
 		context.registerBeanDefinition("fb1", bd1);
 		RootBeanDefinition bd2 = new RootBeanDefinition();
 		bd2.setBeanClass(UntypedFactoryBean.class);
-		bd2.setTargetType(ResolvableType.forClassWithGenerics(FactoryBean.class, ResolvableType.forClassWithGenerics(Set.class, Integer.class)));
+		bd2.setTargetType(ResolvableType.forClassWithGenerics(FactoryBean.class, ResolvableType.forClassWithGenerics(GenericHolder.class, Integer.class)));
 		bd2.setLazyInit(true);
 		context.registerBeanDefinition("fb2", bd2);
 		context.registerBeanDefinition("ip", new RootBeanDefinition(FactoryBeanInjectionPoints.class));
 		context.refresh();
 
-		assertThat(context.getType("&fb1")).isEqualTo(SetFactoryBean.class);
-		assertThat(context.getType("fb1")).isEqualTo(Set.class);
+		assertThat(context.getType("&fb1")).isEqualTo(GenericHolderFactoryBean.class);
+		assertThat(context.getType("fb1")).isEqualTo(GenericHolder.class);
 		assertThat(context.getBeanNamesForType(FactoryBean.class)).hasSize(2);
-		assertThat(context.getBeanNamesForType(SetFactoryBean.class)).hasSize(1);
+		assertThat(context.getBeanNamesForType(GenericHolderFactoryBean.class)).hasSize(1);
 		assertThat(context.getBean("ip", FactoryBeanInjectionPoints.class).factoryBean).isSameAs(context.getBean("&fb1"));
 		assertThat(context.getBean("ip", FactoryBeanInjectionPoints.class).factoryResult).isSameAs(context.getBean("fb1"));
 	}
 
+	@Test
+	void individualBeanWithUnresolvedFactoryBeanTypeAsTargetType() {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
+		RootBeanDefinition bd1 = new RootBeanDefinition();
+		bd1.setBeanClass(GenericHolderFactoryBean.class);
+		bd1.setTargetType(ResolvableType.forClassWithGenerics(FactoryBean.class, ResolvableType.forClassWithGenerics(GenericHolder.class, Object.class)));
+		bd1.setLazyInit(true);
+		context.registerBeanDefinition("fb1", bd1);
+		RootBeanDefinition bd2 = new RootBeanDefinition();
+		bd2.setBeanClass(UntypedFactoryBean.class);
+		bd2.setTargetType(ResolvableType.forClassWithGenerics(FactoryBean.class, ResolvableType.forClassWithGenerics(GenericHolder.class, Integer.class)));
+		bd2.setLazyInit(true);
+		context.registerBeanDefinition("fb2", bd2);
+		context.registerBeanDefinition("ip", new RootBeanDefinition(FactoryResultInjectionPoint.class));
+		context.refresh();
+
+		assertThat(context.getType("&fb1")).isEqualTo(GenericHolderFactoryBean.class);
+		assertThat(context.getType("fb1")).isEqualTo(GenericHolder.class);
+		assertThat(context.getBeanNamesForType(FactoryBean.class)).hasSize(2);
+		assertThat(context.getBean("ip", FactoryResultInjectionPoint.class).factoryResult).isSameAs(context.getBean("fb1"));
+	}
+
 	@Test
 	void individualBeanWithFactoryBeanObjectTypeAsTargetType() {
 		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
 		RootBeanDefinition bd1 = new RootBeanDefinition();
-		bd1.setBeanClass(SetFactoryBean.class);
-		bd1.setTargetType(ResolvableType.forClassWithGenerics(Set.class, String.class));
+		bd1.setBeanClass(GenericHolderFactoryBean.class);
+		bd1.setTargetType(ResolvableType.forClassWithGenerics(GenericHolder.class, String.class));
 		context.registerBeanDefinition("fb1", bd1);
 		RootBeanDefinition bd2 = new RootBeanDefinition();
 		bd2.setBeanClass(UntypedFactoryBean.class);
-		bd2.setTargetType(ResolvableType.forClassWithGenerics(Set.class, Integer.class));
+		bd2.setTargetType(ResolvableType.forClassWithGenerics(GenericHolder.class, Integer.class));
 		context.registerBeanDefinition("fb2", bd2);
 		context.registerBeanDefinition("ip", new RootBeanDefinition(FactoryResultInjectionPoint.class));
 		context.refresh();
 
-		assertThat(context.getType("&fb1")).isEqualTo(SetFactoryBean.class);
-		assertThat(context.getType("fb1")).isEqualTo(Set.class);
+		assertThat(context.getType("&fb1")).isEqualTo(GenericHolderFactoryBean.class);
+		assertThat(context.getType("fb1")).isEqualTo(GenericHolder.class);
 		assertThat(context.getBeanNamesForType(FactoryBean.class)).hasSize(2);
-		assertThat(context.getBeanNamesForType(SetFactoryBean.class)).hasSize(1);
+		assertThat(context.getBeanNamesForType(GenericHolderFactoryBean.class)).hasSize(1);
 		assertThat(context.getBean("ip", FactoryResultInjectionPoint.class).factoryResult).isSameAs(context.getBean("fb1"));
 	}
 
@@ -663,16 +683,18 @@ public boolean isSingleton() {
 		}
 	}
 
-	static class SetFactoryBean implements FactoryBean<Set<String>> {
+	static class GenericHolder<T> {}
+
+	static class GenericHolderFactoryBean implements FactoryBean<GenericHolder<?>> {
 
 		@Override
-		public Set<String> getObject() {
-			return Collections.emptySet();
+		public GenericHolder<?> getObject() {
+			return new GenericHolder<>();
 		}
 
 		@Override
 		public Class<?> getObjectType() {
-			return Set.class;
+			return GenericHolder.class;
 		}
 
 		@Override
@@ -684,13 +706,13 @@ public boolean isSingleton() {
 	static class FactoryResultInjectionPoint {
 
 		@Autowired
-		Set<String> factoryResult;
+		GenericHolder<String> factoryResult;
 	}
 
 	static class FactoryBeanInjectionPoints extends FactoryResultInjectionPoint {
 
 		@Autowired
-		FactoryBean<Set<String>> factoryBean;
+		FactoryBean<GenericHolder<String>> factoryBean;
 	}
 }