Add missing hints for <Application>__EnvironmentPostProcessor

This commit fixes the initialization of the environment in a native
image by adding the necessary reflection hints so that the generated
EnvironmentPostProcessor is found.

Closes gh-48408

Author: snicoll

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/env/EnvironmentPostProcessorApplicationListener.java

@@ -24,7 +24,9 @@
 
 import org.springframework.aot.AotDetector;
 import org.springframework.aot.generate.GeneratedClass;
+import org.springframework.aot.generate.GeneratedTypeReference;
 import org.springframework.aot.generate.GenerationContext;
+import org.springframework.aot.hint.MemberCategory;
 import org.springframework.beans.BeanInstantiationException;
 import org.springframework.beans.BeanUtils;
 import org.springframework.beans.factory.aot.BeanFactoryInitializationAotContribution;
@@ -59,7 +61,7 @@
  */
 public class EnvironmentPostProcessorApplicationListener implements SmartApplicationListener, Ordered {
 
-	private static final String AOT_FEATURE_NAME = "EnvironmentPostProcessor";
+	static final String AOT_FEATURE_NAME = "EnvironmentPostProcessor";
 
 	/**
 	 * The default order for the processor.
@@ -234,6 +236,10 @@ public void applyTo(GenerationContext generationContext,
 				method.addParameter(SpringApplication.class, "application");
 				method.addCode(generateActiveProfilesInitializeCode());
 			});
+			generationContext.getRuntimeHints()
+				.reflection()
+				.registerType(GeneratedTypeReference.of(generatedClass.getName()),
+						MemberCategory.INVOKE_PUBLIC_CONSTRUCTORS);
 		}
 
 		private CodeBlock generateActiveProfilesInitializeCode() {

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/env/EnvironmentPostProcessorApplicationListenerTests.java

@@ -35,6 +35,10 @@
 import org.junit.jupiter.api.io.TempDir;
 
 import org.springframework.aot.AotDetector;
+import org.springframework.aot.generate.GenerationContext;
+import org.springframework.aot.hint.MemberCategory;
+import org.springframework.aot.hint.TypeReference;
+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.support.DefaultListableBeanFactory;
@@ -209,6 +213,24 @@ void aotContributionRegistersActiveProfiles() {
 			});
 		}
 
+		@Test
+		void aotContributionRegistersReflectionHints() {
+			GenericApplicationContext applicationContext = new GenericApplicationContext();
+			ConfigurableEnvironment environment = new StandardEnvironment();
+			environment.setActiveProfiles("one", "two");
+			applicationContext.getBeanFactory().registerSingleton("environment", environment);
+			BeanFactoryInitializationAotContribution aotContribution = new EnvironmentBeanFactoryInitializationAotProcessor()
+				.processAheadOfTime(applicationContext.getBeanFactory());
+			assertThat(aotContribution).isNotNull();
+			GenerationContext generationContext = new TestGenerationContext();
+			aotContribution.applyTo(generationContext, null);
+			assertThat(RuntimeHintsPredicates.reflection()
+				.onType(TypeReference.of(TestGenerationContext.TEST_TARGET + "__"
+						+ EnvironmentPostProcessorApplicationListener.AOT_FEATURE_NAME))
+				.withMemberCategory(MemberCategory.INVOKE_PUBLIC_CONSTRUCTORS))
+				.accepts(generationContext.getRuntimeHints());
+		}
+
 		@Test
 		void shouldUseAotEnvironmentPostProcessor() {
 			SpringApplication application = new SpringApplication(ExampleAotProcessedApp.class);