Contribute reflection hints for JsonComponent inner classes

Closes gh-33089

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/jackson/JsonComponentModule.java

@@ -17,6 +17,9 @@
 package org.springframework.boot.jackson;
 
 import java.lang.reflect.Modifier;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.function.BiConsumer;
 
@@ -26,6 +29,9 @@ import com.fasterxml.jackson.databind.KeyDeserializer;
 import com.fasterxml.jackson.databind.Module;
 import com.fasterxml.jackson.databind.module.SimpleModule;
 
+import org.springframework.aot.generate.GenerationContext;
+import org.springframework.aot.hint.MemberCategory;
+import org.springframework.aot.hint.ReflectionHints;
 import org.springframework.beans.BeanUtils;
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanFactory;
@@ -33,6 +39,10 @@ import org.springframework.beans.factory.BeanFactoryAware;
 import org.springframework.beans.factory.HierarchicalBeanFactory;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.beans.factory.ListableBeanFactory;
+import org.springframework.beans.factory.aot.BeanFactoryInitializationAotContribution;
+import org.springframework.beans.factory.aot.BeanFactoryInitializationAotProcessor;
+import org.springframework.beans.factory.aot.BeanFactoryInitializationCode;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.boot.jackson.JsonComponent.Scope;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.annotation.MergedAnnotation;
@@ -108,7 +118,7 @@ public class JsonComponentModule extends SimpleModule implements BeanFactoryAwar
 		}
 	}
 
-	private boolean isSuitableInnerClass(Class<?> innerClass) {
+	private static boolean isSuitableInnerClass(Class<?> innerClass) {
 		return !Modifier.isAbstract(innerClass.getModifiers()) && (JsonSerializer.class.isAssignableFrom(innerClass)
 				|| JsonDeserializer.class.isAssignableFrom(innerClass)
 				|| KeyDeserializer.class.isAssignableFrom(innerClass));
@@ -148,4 +158,44 @@ public class JsonComponentModule extends SimpleModule implements BeanFactoryAwar
 		}
 	}
 
+	static class JsonComponentBeanFactoryInitializationAotProcessor implements BeanFactoryInitializationAotProcessor {
+
+		@Override
+		public BeanFactoryInitializationAotContribution processAheadOfTime(
+				ConfigurableListableBeanFactory beanFactory) {
+			String[] jsonComponents = beanFactory.getBeanNamesForAnnotation(JsonComponent.class);
+			Map<Class<?>, List<Class<?>>> innerComponents = new HashMap<>();
+			for (String jsonComponent : jsonComponents) {
+				Class<?> type = beanFactory.getType(jsonComponent, true);
+				for (Class<?> declaredClass : type.getDeclaredClasses()) {
+					if (isSuitableInnerClass(declaredClass)) {
+						innerComponents.computeIfAbsent(type, (t) -> new ArrayList<>()).add(declaredClass);
+					}
+				}
+			}
+			return innerComponents.isEmpty() ? null : new JsonComponentAotContribution(innerComponents);
+		}
+
+	}
+
+	private static class JsonComponentAotContribution implements BeanFactoryInitializationAotContribution {
+
+		private final Map<Class<?>, List<Class<?>>> innerComponents;
+
+		public JsonComponentAotContribution(Map<Class<?>, List<Class<?>>> innerComponents) {
+			this.innerComponents = innerComponents;
+		}
+
+		@Override
+		public void applyTo(GenerationContext generationContext,
+				BeanFactoryInitializationCode beanFactoryInitializationCode) {
+			ReflectionHints reflection = generationContext.getRuntimeHints().reflection();
+			this.innerComponents.forEach((outer, inners) -> {
+				reflection.registerType(outer, MemberCategory.DECLARED_CLASSES);
+				inners.forEach((inner) -> reflection.registerType(inner, MemberCategory.INVOKE_DECLARED_CONSTRUCTORS));
+			});
+		}
+
+	}
+
 }

spring-boot-project/spring-boot/src/main/resources/META-INF/spring/aot.factories

@@ -14,7 +14,8 @@ org.springframework.boot.web.embedded.undertow.UndertowWebServer.UndertowWebServ
 org.springframework.boot.web.server.MimeMappings.MimeMappingsRuntimeHints
 
 org.springframework.beans.factory.aot.BeanFactoryInitializationAotProcessor=\
-org.springframework.boot.context.properties.ConfigurationPropertiesBeanFactoryInitializationAotProcessor
+org.springframework.boot.context.properties.ConfigurationPropertiesBeanFactoryInitializationAotProcessor,\
+org.springframework.boot.jackson.JsonComponentModule.JsonComponentBeanFactoryInitializationAotProcessor
 
 org.springframework.beans.factory.aot.BeanRegistrationAotProcessor=\
 org.springframework.boot.context.properties.ConfigurationPropertiesBeanRegistrationAotProcessor,\

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/jackson/JsonComponentModuleTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -27,6 +27,16 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.aot.hint.MemberCategory;
+import org.springframework.aot.hint.RuntimeHints;
+import org.springframework.aot.hint.predicate.RuntimeHintsPredicates;
+import org.springframework.aot.test.generate.TestGenerationContext;
+import org.springframework.beans.factory.aot.BeanFactoryInitializationAotContribution;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.boot.jackson.JsonComponentModule.JsonComponentBeanFactoryInitializationAotProcessor;
+import org.springframework.boot.jackson.JsonComponentModuleTests.ComponentWithInnerAbstractClass.AbstractSerializer;
+import org.springframework.boot.jackson.JsonComponentModuleTests.ComponentWithInnerAbstractClass.ConcreteSerializer;
+import org.springframework.boot.jackson.JsonComponentModuleTests.ComponentWithInnerAbstractClass.NotSuitable;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -112,6 +122,25 @@ class JsonComponentModuleTests {
 		assertDeserializeForSpecifiedClasses(module);
 	}
 
+	@Test
+	void aotContributionRegistersReflectionHintsForSuitableInnerClasses() {
+		load(ComponentWithInnerAbstractClass.class);
+		ConfigurableListableBeanFactory beanFactory = this.context.getBeanFactory();
+		BeanFactoryInitializationAotContribution contribution = new JsonComponentBeanFactoryInitializationAotProcessor()
+				.processAheadOfTime(beanFactory);
+		TestGenerationContext generationContext = new TestGenerationContext();
+		contribution.applyTo(generationContext, null);
+		RuntimeHints runtimeHints = generationContext.getRuntimeHints();
+		assertThat(RuntimeHintsPredicates.reflection().onType(ComponentWithInnerAbstractClass.class)
+				.withMemberCategory(MemberCategory.DECLARED_CLASSES)).accepts(runtimeHints);
+		assertThat(RuntimeHintsPredicates.reflection().onType(ConcreteSerializer.class)
+				.withMemberCategory(MemberCategory.INVOKE_DECLARED_CONSTRUCTORS)).accepts(runtimeHints);
+		assertThat(RuntimeHintsPredicates.reflection().onType(AbstractSerializer.class)
+				.withMemberCategory(MemberCategory.INVOKE_DECLARED_CONSTRUCTORS).negate()).accepts(runtimeHints);
+		assertThat(RuntimeHintsPredicates.reflection().onType(NotSuitable.class)
+				.withMemberCategory(MemberCategory.INVOKE_DECLARED_CONSTRUCTORS).negate()).accepts(runtimeHints);
+	}
+
 	private void load(Class<?>... configs) {
 		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
 		context.register(configs);
@@ -181,7 +210,7 @@ class JsonComponentModuleTests {
 	@JsonComponent
 	static class ComponentWithInnerAbstractClass {
 
-		static class AbstractSerializer extends NameAndAgeJsonComponent.Serializer {
+		static abstract class AbstractSerializer extends NameAndAgeJsonComponent.Serializer {
 
 		}
 
@@ -189,6 +218,10 @@ class JsonComponentModuleTests {
 
 		}
 
+		static class NotSuitable {
+
+		}
+
 	}
 
 	@JsonComponent(scope = JsonComponent.Scope.KEYS)