Update ConfigurationClassPostProcessor AOT support

Update `ConfigurationClassPostProcessor` so that it provides AOT
contributions via the `BeanFactoryInitializationAotProcessor`
interface.

See gh-28414

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

@@ -0,0 +1,163 @@
+/*
+ * Copyright 2002-2022 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.
+ * 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.context.annotation;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.BiConsumer;
+import java.util.function.Consumer;
+
+import javax.lang.model.element.Modifier;
+
+import org.assertj.core.api.InstanceOfAssertFactories;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.aot.generate.DefaultGenerationContext;
+import org.springframework.aot.generate.GeneratedMethods;
+import org.springframework.aot.generate.InMemoryGeneratedFiles;
+import org.springframework.aot.generate.MethodGenerator;
+import org.springframework.aot.generate.MethodReference;
+import org.springframework.aot.test.generator.compile.Compiled;
+import org.springframework.aot.test.generator.compile.TestCompiler;
+import org.springframework.beans.factory.aot.BeanFactoryInitializationAotContribution;
+import org.springframework.beans.factory.aot.BeanFactoryInitializationCode;
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
+import org.springframework.beans.factory.support.RootBeanDefinition;
+import org.springframework.beans.testfixture.beans.factory.generator.SimpleConfiguration;
+import org.springframework.context.testfixture.context.generator.annotation.ImportAwareConfiguration;
+import org.springframework.context.testfixture.context.generator.annotation.ImportConfiguration;
+import org.springframework.javapoet.CodeBlock;
+import org.springframework.javapoet.JavaFile;
+import org.springframework.javapoet.MethodSpec;
+import org.springframework.javapoet.ParameterizedTypeName;
+import org.springframework.javapoet.TypeSpec;
+import org.springframework.lang.Nullable;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.entry;
+
+/**
+ * Tests for {@link ConfigurationClassPostProcessor} AOT contributions.
+ *
+ * @author Phillip Webb
+ * @author Stephane Nicoll
+ */
+class ConfigurationClassPostProcessorAotContributionTests {
+
+	private DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
+
+	private InMemoryGeneratedFiles generatedFiles = new InMemoryGeneratedFiles();
+
+	private DefaultGenerationContext generationContext = new DefaultGenerationContext(
+			this.generatedFiles);
+
+	private MockBeanFactoryInitializationCode beanFactoryInitializationCode = new MockBeanFactoryInitializationCode();
+
+	@Test
+	void applyToWhenHasImportAwareConfigurationRegistersBeanPostProcessorWithMapEntry() {
+		BeanFactoryInitializationAotContribution contribution = getContribution(
+				ImportConfiguration.class);
+		contribution.applyTo(this.generationContext, this.beanFactoryInitializationCode);
+		testCompiledResult((initializer, compiled) -> {
+			DefaultListableBeanFactory freshBeanFactory = new DefaultListableBeanFactory();
+			initializer.accept(freshBeanFactory);
+			ImportAwareAotBeanPostProcessor postProcessor = (ImportAwareAotBeanPostProcessor) freshBeanFactory
+					.getBeanPostProcessors().get(0);
+			assertPostProcessorEntry(postProcessor, ImportAwareConfiguration.class,
+					ImportConfiguration.class);
+		});
+	}
+
+	@Test
+	void applyToWhenHasImportAwareConfigurationRegistersHints() {
+		BeanFactoryInitializationAotContribution contribution = getContribution(
+				ImportConfiguration.class);
+		contribution.applyTo(this.generationContext, this.beanFactoryInitializationCode);
+		assertThat(generationContext.getRuntimeHints().resources().resourcePatterns())
+				.singleElement()
+				.satisfies(resourceHint -> assertThat(resourceHint.getIncludes())
+						.containsOnly(
+								"org/springframework/context/testfixture/context/generator/annotation/ImportConfiguration.class"));
+	}
+
+	@Test
+	void processAheadOfTimeWhenNoImportAwareConfigurationReturnsNull() {
+		assertThat(getContribution(SimpleConfiguration.class)).isNull();
+	}
+
+	@Nullable
+	private BeanFactoryInitializationAotContribution getContribution(Class<?> type) {
+		this.beanFactory.registerBeanDefinition("configuration",
+				new RootBeanDefinition(type));
+		ConfigurationClassPostProcessor postProcessor = new ConfigurationClassPostProcessor();
+		postProcessor.postProcessBeanFactory(this.beanFactory);
+		return postProcessor.processAheadOfTime(this.beanFactory);
+	}
+
+	@SuppressWarnings("unchecked")
+	private void testCompiledResult(
+			BiConsumer<Consumer<DefaultListableBeanFactory>, Compiled> result) {
+		JavaFile javaFile = createJavaFile();
+		this.generationContext.writeGeneratedContent();
+		TestCompiler.forSystem().withFiles(this.generatedFiles).compile(javaFile::writeTo,
+				compiled -> result.accept(compiled.getInstance(Consumer.class),
+						compiled));
+	}
+
+	private JavaFile createJavaFile() {
+		MethodReference methodReference = this.beanFactoryInitializationCode.initializers
+				.get(0);
+		TypeSpec.Builder builder = TypeSpec.classBuilder("TestConsumer");
+		builder.addModifiers(Modifier.PUBLIC);
+		builder.addSuperinterface(ParameterizedTypeName.get(Consumer.class,
+				DefaultListableBeanFactory.class));
+		builder.addMethod(MethodSpec.methodBuilder("accept").addModifiers(Modifier.PUBLIC)
+				.addParameter(DefaultListableBeanFactory.class, "beanFactory")
+				.addStatement(
+						methodReference.toInvokeCodeBlock(CodeBlock.of("beanFactory")))
+				.build());
+		this.beanFactoryInitializationCode.generatedMethods
+				.doWithMethodSpecs(builder::addMethod);
+		return JavaFile.builder("__", builder.build()).build();
+	}
+
+	private void assertPostProcessorEntry(ImportAwareAotBeanPostProcessor postProcessor,
+			Class<?> key, Class<?> value) {
+		assertThat(postProcessor).extracting("importsMapping")
+				.asInstanceOf(InstanceOfAssertFactories.MAP)
+				.containsExactly(entry(key.getName(), value.getName()));
+	}
+
+	class MockBeanFactoryInitializationCode implements BeanFactoryInitializationCode {
+
+		private final GeneratedMethods generatedMethods = new GeneratedMethods();
+
+		private final List<MethodReference> initializers = new ArrayList<>();
+
+		@Override
+		public MethodGenerator getMethodGenerator() {
+			return this.generatedMethods;
+		}
+
+		@Override
+		public void addInitializer(MethodReference methodReference) {
+			this.initializers.add(methodReference);
+		}
+
+	}
+
+}