Rename AutoConfigurationLoader to ImportCandidates

Move the class to a more suitable package, and load the files from
META-INF/spring/<fqn>.imports

See gh-29872

Author: mhalbritter

buildSrc/src/main/java/org/springframework/boot/build/autoconfigure/AutoConfigurationMetadata.java

@@ -66,7 +66,7 @@ public AutoConfigurationMetadata() {
 				.withPathSensitivity(PathSensitivity.RELATIVE).withPropertyName("spring.factories");
 		getInputs()
 				.file((Callable<File>) () -> new File(this.sourceSet.getOutput().getResourcesDir(),
-						"META-INF/spring-boot/org.springframework.boot.autoconfigure.AutoConfiguration"))
+						"META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports"))
 				.withPathSensitivity(PathSensitivity.RELATIVE)
 				.withPropertyName("org.springframework.boot.autoconfigure.AutoConfiguration");
 
@@ -137,17 +137,17 @@ private Set<String> readSpringFactories() throws IOException {
 
 	/**
 	 * Reads auto-configurations from
-	 * META-INF/spring-boot/org.springframework.boot.autoconfigure.AutoConfiguration.
+	 * META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports.
 	 * @return auto-configurations
 	 */
 	private List<String> readAutoConfigurationsFile() throws IOException {
 		File file = new File(this.sourceSet.getOutput().getResourcesDir(),
-				"META-INF/spring-boot/org.springframework.boot.autoconfigure.AutoConfiguration");
+				"META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports");
 		if (!file.exists()) {
 			return Collections.emptyList();
 		}
 		// Nearly identical copy of
-		// org.springframework.boot.autoconfigure.AutoConfigurationLoader.readAutoConfigurations
+		// org.springframework.boot.context.annotation.ImportCandidates.load
 		try (BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(file)))) {
 			List<String> autoConfigurations = new ArrayList<>();
 			String line;

buildSrc/src/main/java/org/springframework/boot/build/test/autoconfigure/TestSliceMetadata.java

@@ -106,7 +106,7 @@ private Properties readTestSlices() throws IOException {
 			Properties springFactories = readSpringFactories(
 					new File(this.sourceSet.getOutput().getResourcesDir(), "META-INF/spring.factories"));
 			readTestSlicesDirectory(springFactories,
-					new File(this.sourceSet.getOutput().getResourcesDir(), "META-INF/spring-boot/"));
+					new File(this.sourceSet.getOutput().getResourcesDir(), "META-INF/spring/"));
 			for (File classesDir : this.sourceSet.getOutput().getClassesDirs()) {
 				addTestSlices(testSlices, classesDir, metadataReaderFactory, springFactories);
 			}
@@ -123,14 +123,17 @@ private Properties readTestSlices() throws IOException {
 	 * @param directory directory to scan
 	 */
 	private void readTestSlicesDirectory(Properties springFactories, File directory) {
-		File[] files = directory.listFiles();
+		File[] files = directory.listFiles((dir, name) -> name.endsWith(".imports"));
 		if (files == null) {
 			return;
 		}
 		for (File file : files) {
 			try {
 				List<String> lines = removeComments(Files.readAllLines(file.toPath()));
-				springFactories.setProperty(file.getName(), StringUtils.collectionToCommaDelimitedString(lines));
+				String fileNameWithoutExtension = file.getName().substring(0,
+						file.getName().length() - ".imports".length());
+				springFactories.setProperty(fileNameWithoutExtension,
+						StringUtils.collectionToCommaDelimitedString(lines));
 			}
 			catch (IOException ex) {
 				throw new UncheckedIOException("Failed to read file " + file, ex);

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/resources/META-INF/spring-boot/org.springframework.boot.autoconfigure.AutoConfiguration renamed to spring-boot-project/spring-boot-actuator-autoconfigure/src/main/resources/META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports

@@ -24,6 +24,7 @@
 
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.context.annotation.ImportCandidates;
 import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.io.support.SpringFactoriesLoader;
@@ -34,9 +35,8 @@
  * {@link Configuration @Configuration} with the exception that
  * {@literal Configuration#proxyBeanMethods() proxyBeanMethods} is always {@code false}.
  * <p>
- * They are located using the {@link AutoConfigurationLoader} and the
- * {@link SpringFactoriesLoader} mechanism (keyed against
- * {@link EnableAutoConfiguration}).
+ * They are located using {@link ImportCandidates} and the {@link SpringFactoriesLoader}
+ * mechanism (keyed against {@link EnableAutoConfiguration}).
  * <p>
  * Generally auto-configuration classes are marked as {@link Conditional @Conditional}
  * (most often using {@link ConditionalOnClass @ConditionalOnClass} and

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfiguration.java

@@ -21,6 +21,7 @@
 import java.util.List;
 
 import org.springframework.beans.factory.BeanClassLoaderAware;
+import org.springframework.boot.context.annotation.ImportCandidates;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.io.support.SpringFactoriesLoader;
 import org.springframework.core.type.classreading.MetadataReader;
@@ -63,11 +64,9 @@ private boolean isAutoConfiguration(MetadataReader metadataReader) {
 
 	protected List<String> getAutoConfigurations() {
 		if (this.autoConfigurations == null) {
-			List<String> autoConfigurations = new ArrayList<>();
-			autoConfigurations.addAll(
+			List<String> autoConfigurations = new ArrayList<>(
 					SpringFactoriesLoader.loadFactoryNames(EnableAutoConfiguration.class, this.beanClassLoader));
-			autoConfigurations
-					.addAll(new AutoConfigurationLoader().loadNames(AutoConfiguration.class, this.beanClassLoader));
+			ImportCandidates.load(AutoConfiguration.class, this.beanClassLoader).forEach(autoConfigurations::add);
 			this.autoConfigurations = autoConfigurations;
 		}
 		return this.autoConfigurations;

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfigurationExcludeFilter.java

@@ -40,6 +40,7 @@
 import org.springframework.beans.factory.BeanFactoryAware;
 import org.springframework.beans.factory.NoSuchBeanDefinitionException;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.boot.context.annotation.ImportCandidates;
 import org.springframework.boot.context.properties.bind.Binder;
 import org.springframework.context.EnvironmentAware;
 import org.springframework.context.ResourceLoaderAware;
@@ -168,7 +169,7 @@ protected Class<?> getAnnotationClass() {
 
 	/**
 	 * Return the auto-configuration class names that should be considered. By default
-	 * this method will load candidates using {@link AutoConfigurationLoader} with
+	 * this method will load candidates using {@link ImportCandidates} with
 	 * {@link #getSpringFactoriesLoaderFactoryClass()}. For backward compatible reasons it
 	 * will also consider {@link SpringFactoriesLoader} with
 	 * {@link #getSpringFactoriesLoaderFactoryClass()}.
@@ -178,12 +179,11 @@ protected Class<?> getAnnotationClass() {
 	 * @return a list of candidate configurations
 	 */
 	protected List<String> getCandidateConfigurations(AnnotationMetadata metadata, AnnotationAttributes attributes) {
-		List<String> configurations = new ArrayList<>();
-		configurations.addAll(
+		List<String> configurations = new ArrayList<>(
 				SpringFactoriesLoader.loadFactoryNames(getSpringFactoriesLoaderFactoryClass(), getBeanClassLoader()));
-		configurations.addAll(new AutoConfigurationLoader().loadNames(AutoConfiguration.class, getBeanClassLoader()));
+		ImportCandidates.load(AutoConfiguration.class, getBeanClassLoader()).forEach(configurations::add);
 		Assert.notEmpty(configurations,
-				"No auto configuration classes found in META-INF/spring.factories nor in META-INF/spring-boot/org.springframework.boot.autoconfigure.AutoConfiguration. If you "
+				"No auto configuration classes found in META-INF/spring.factories nor in META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports. If you "
 						+ "are using a custom packaging, make sure that file is correct.");
 		return configurations;
 	}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfigurationImportSelector.java

@@ -26,6 +26,7 @@
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.context.annotation.ImportCandidates;
 import org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory;
 import org.springframework.boot.web.servlet.server.ServletWebServerFactory;
 import org.springframework.context.annotation.Conditional;
@@ -60,7 +61,7 @@
  * and classes can be searched.
  * <p>
  * Auto-configuration classes are regular Spring {@link Configuration @Configuration}
- * beans. They are located using the {@link AutoConfigurationLoader} and the
+ * beans. They are located using {@link ImportCandidates} and the
  * {@link SpringFactoriesLoader} mechanism (keyed against this class). Generally
  * auto-configuration beans are {@link Conditional @Conditional} beans (most often using
  * {@link ConditionalOnClass @ConditionalOnClass} and

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/EnableAutoConfiguration.java

@@ -59,8 +59,8 @@
 
 	/**
 	 * The auto-configuration classes that should be imported. When empty, the classes are
-	 * specified using a file in {@code META-INF/spring-boot} where the file name is the
-	 * fully-qualified name of the annotated class.
+	 * specified using a file in {@code META-INF/spring} where the file name is the
+	 * fully-qualified name of the annotated class, suffixed with '.imports'.
 	 * @return the classes to import
 	 */
 	@AliasFor("value")

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/ImportAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 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.
@@ -28,6 +28,7 @@
 import java.util.Set;
 
 import org.springframework.boot.context.annotation.DeterminableImports;
+import org.springframework.boot.context.annotation.ImportCandidates;
 import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.annotation.AnnotationUtils;
@@ -95,9 +96,9 @@ private Collection<String> getConfigurationsForAnnotation(Class<?> source, Annot
 	}
 
 	protected Collection<String> loadFactoryNames(Class<?> source) {
-		List<String> factoryNames = new ArrayList<>();
-		factoryNames.addAll(SpringFactoriesLoader.loadFactoryNames(source, getBeanClassLoader()));
-		factoryNames.addAll(new AutoConfigurationLoader().loadNames(source, getBeanClassLoader()));
+		List<String> factoryNames = new ArrayList<>(
+				SpringFactoriesLoader.loadFactoryNames(source, getBeanClassLoader()));
+		ImportCandidates.load(source, getBeanClassLoader()).forEach(factoryNames::add);
 		return factoryNames;
 	}