Find all @ComponentScan and @PropertySource annotations

Prior to this commit, Spring failed to find multiple composed
@ComponentScan and @PropertySource annotations or multiple
@ComponentScans and @PropertySources container annotations. The reason
was due to lacking support in the AnnotatedTypeMetadata API.

This commit introduces support for finding all @ComponentScan and
@PropertySource annotations by making use of the new
getMergedRepeatableAnnotationAttributes() method in
AnnotatedTypeMetadata.

Closes gh-30941
See gh-31041

spring-context/src/main/java/org/springframework/context/annotation/AnnotationConfigUtils.java

@@ -17,9 +17,7 @@
 package org.springframework.context.annotation;
 
 import java.lang.annotation.Annotation;
-import java.util.Collections;
 import java.util.LinkedHashSet;
-import java.util.Map;
 import java.util.Set;
 
 import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
@@ -51,6 +49,7 @@ import org.springframework.util.ClassUtils;
  * @author Chris Beams
  * @author Phillip Webb
  * @author Stephane Nicoll
+ * @author Sam Brannen
  * @since 2.5
  * @see ContextAnnotationAutowireCandidateResolver
  * @see ConfigurationClassPostProcessor
@@ -281,33 +280,10 @@ public abstract class AnnotationConfigUtils {
 		return AnnotationAttributes.fromMap(metadata.getAnnotationAttributes(annotationTypeName));
 	}
 
-	@SuppressWarnings("unchecked")
 	static Set<AnnotationAttributes> attributesForRepeatable(AnnotationMetadata metadata,
-			Class<? extends Annotation> containerType, Class<? extends Annotation> annotationType) {
+			Class<? extends Annotation> annotationType, Class<? extends Annotation> containerType) {
 
-		Set<AnnotationAttributes> result = new LinkedHashSet<>();
-
-		// Direct annotation present or meta-present?
-		addAttributesIfNotNull(result, metadata.getAnnotationAttributes(annotationType.getName()));
-
-		// Container annotation present or meta-present?
-		Map<String, Object> container = metadata.getAnnotationAttributes(containerType.getName());
-		if (container != null && container.containsKey("value")) {
-			for (Map<String, Object> containedAttributes : (Map<String, Object>[]) container.get("value")) {
-				addAttributesIfNotNull(result, containedAttributes);
-			}
-		}
-
-		// Return merged result
-		return Collections.unmodifiableSet(result);
-	}
-
-	private static void addAttributesIfNotNull(
-			Set<AnnotationAttributes> result, @Nullable Map<String, Object> attributes) {
-
-		if (attributes != null) {
-			result.add(AnnotationAttributes.fromMap(attributes));
-		}
+		return metadata.getMergedRepeatableAnnotationAttributes(annotationType, containerType, false);
 	}
 
 }

spring-context/src/main/java/org/springframework/context/annotation/ComponentScan.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -46,6 +46,10 @@ import org.springframework.core.type.filter.TypeFilter;
  *
  * <p>See {@link Configuration @Configuration}'s Javadoc for usage examples.
  *
+ * <p>{@code @ComponentScan} can be used as a <em>{@linkplain Repeatable repeatable}</em>
+ * annotation. {@code @ComponentScan} may also be used as a <em>meta-annotation</em>
+ * to create custom <em>composed annotations</em> with attribute overrides.
+ *
  * @author Chris Beams
  * @author Juergen Hoeller
  * @author Sam Brannen

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java

@@ -267,8 +267,8 @@ class ConfigurationClassParser {
 
 		// Process any @PropertySource annotations
 		for (AnnotationAttributes propertySource : AnnotationConfigUtils.attributesForRepeatable(
-				sourceClass.getMetadata(), PropertySources.class,
-				org.springframework.context.annotation.PropertySource.class)) {
+				sourceClass.getMetadata(), org.springframework.context.annotation.PropertySource.class,
+				PropertySources.class)) {
 			if (this.propertySourceRegistry != null) {
 				this.propertySourceRegistry.processPropertySource(propertySource);
 			}
@@ -280,7 +280,7 @@ class ConfigurationClassParser {
 
 		// Process any @ComponentScan annotations
 		Set<AnnotationAttributes> componentScans = AnnotationConfigUtils.attributesForRepeatable(
-				sourceClass.getMetadata(), ComponentScans.class, ComponentScan.class);
+				sourceClass.getMetadata(), ComponentScan.class, ComponentScans.class);
 		if (!componentScans.isEmpty() &&
 				!this.conditionEvaluator.shouldSkip(sourceClass.getMetadata(), ConfigurationPhase.REGISTER_BEAN)) {
 			for (AnnotationAttributes componentScan : componentScans) {

spring-context/src/main/java/org/springframework/context/annotation/PropertySource.java

@@ -147,11 +147,9 @@ import org.springframework.core.io.support.PropertySourceFactory;
  * ConfigurableEnvironment} and {@link org.springframework.core.env.MutablePropertySources
  * MutablePropertySources} javadocs for details.
  *
- * <p><b>NOTE: This annotation is repeatable according to Java 8 conventions.</b>
- * However, all such {@code @PropertySource} annotations need to be declared at the same
- * level: either directly on the configuration class or as meta-annotations on the
- * same custom annotation. Mixing direct annotations and meta-annotations is not
- * recommended since direct annotations will effectively override meta-annotations.
+ * <p>{@code @PropertySource} can be used as a <em>{@linkplain Repeatable repeatable}</em>
+ * annotation. {@code @PropertySource} may also be used as a <em>meta-annotation</em>
+ * to create custom <em>composed annotations</em> with attribute overrides.
  *
  * @author Chris Beams
  * @author Juergen Hoeller

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

@@ -44,6 +44,7 @@ import org.springframework.beans.factory.annotation.CustomAutowireConfigurer;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
+import org.springframework.context.ApplicationContext;
 import org.springframework.context.EnvironmentAware;
 import org.springframework.context.ResourceLoaderAware;
 import org.springframework.context.annotation.ComponentScan.Filter;
@@ -143,6 +144,15 @@ public class ComponentScanAnnotationIntegrationTests {
 			.isTrue();
 	}
 
+	@Test
+	void multipleComposedComponentScanAnnotations() {  // gh-30941
+		ApplicationContext ctx = new AnnotationConfigApplicationContext(MultipleComposedAnnotationsConfig.class);
+		ctx.getBean(MultipleComposedAnnotationsConfig.class);
+		assertContextContainsBean(ctx, "componentScanAnnotationIntegrationTests.MultipleComposedAnnotationsConfig");
+		assertContextContainsBean(ctx, "simpleComponent");
+		assertContextContainsBean(ctx, "barComponent");
+	}
+
 	@Test
 	public void viaBeanRegistration() {
 		DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
@@ -267,6 +277,10 @@ public class ComponentScanAnnotationIntegrationTests {
 		assertThat(ctx.containsBean("fooServiceImpl")).isTrue();
 	}
 
+	private static void assertContextContainsBean(ApplicationContext ctx, String beanName) {
+		assertThat(ctx.containsBean(beanName)).as("context contains bean " + beanName).isTrue();
+	}
+
 
 	@Configuration
 	@ComponentScan
@@ -278,10 +292,25 @@ public class ComponentScanAnnotationIntegrationTests {
 		String[] basePackages() default {};
 	}
 
+	@Configuration
+	@ComponentScan
+	@Retention(RetentionPolicy.RUNTIME)
+	@Target(ElementType.TYPE)
+	public @interface ComposedConfiguration2 {
+
+		@AliasFor(annotation = ComponentScan.class)
+		String[] basePackages() default {};
+	}
+
 	@ComposedConfiguration(basePackages = "org.springframework.context.annotation.componentscan.simple")
 	public static class ComposedAnnotationConfig {
 	}
 
+	@ComposedConfiguration(basePackages = "org.springframework.context.annotation.componentscan.simple")
+	@ComposedConfiguration2(basePackages = "example.scannable.sub")
+	static class MultipleComposedAnnotationsConfig {
+	}
+
 	public static class AwareTypeFilter implements TypeFilter, EnvironmentAware,
 			ResourceLoaderAware, BeanClassLoaderAware, BeanFactoryAware {
 

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -32,6 +32,7 @@ import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.BeanDefinitionStoreException;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.testfixture.beans.TestBean;
+import org.springframework.context.ApplicationContext;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.core.annotation.AliasFor;
 import org.springframework.core.env.Environment;
@@ -239,6 +240,14 @@ class PropertySourceAnnotationTests {
 		}
 	}
 
+	@Test
+	void multipleComposedPropertySourceAnnotations() {  // gh-30941
+		ConfigurableApplicationContext ctx = new AnnotationConfigApplicationContext(MultipleComposedAnnotationsConfig.class);
+		ctx.getBean(MultipleComposedAnnotationsConfig.class);
+		assertEnvironmentContainsProperties(ctx, "from.p1", "from.p2", "from.p3", "from.p4", "from.p5");
+		ctx.close();
+	}
+
 	@Test
 	void withNamedPropertySources() {
 		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(ConfigWithNamedPropertySources.class);
@@ -305,6 +314,17 @@ class PropertySourceAnnotationTests {
 	}
 
 
+	private static void assertEnvironmentContainsProperties(ApplicationContext ctx, String... names) {
+		for (String name : names) {
+			assertThat(ctx.getEnvironment().containsProperty(name)).as("environment contains property " + name).isTrue();
+		}
+	}
+
+	private static void assertEnvironmentContainsProperty(ApplicationContext ctx, String name) {
+		assertThat(ctx.getEnvironment().containsProperty(name)).as("environment contains property " + name).isTrue();
+	}
+
+
 	@Configuration
 	@PropertySource("classpath:${unresolvable}/p1.properties")
 	static class ConfigWithUnresolvablePlaceholder {
@@ -496,6 +516,28 @@ class PropertySourceAnnotationTests {
 	static class ConfigWithRepeatedPropertySourceAnnotationsOnComposedAnnotation {
 	}
 
+	@Retention(RetentionPolicy.RUNTIME)
+	@PropertySource("classpath:org/springframework/context/annotation/p1.properties")
+	@interface PropertySource1 {
+	}
+
+	@Retention(RetentionPolicy.RUNTIME)
+	@PropertySource("classpath:org/springframework/context/annotation/p2.properties")
+	@PropertySources({
+		@PropertySource("classpath:org/springframework/context/annotation/p3.properties"),
+	})
+	@interface PropertySource23 {
+	}
+
+	@Configuration
+	@PropertySource1
+	@PropertySource23
+	@PropertySources({
+		@PropertySource("classpath:org/springframework/context/annotation/p4.properties")
+	})
+	@PropertySource("classpath:org/springframework/context/annotation/p5.properties")
+	static class MultipleComposedAnnotationsConfig {
+	}
 
 	@Configuration
 	@PropertySources({

spring-context/src/test/resources/org/springframework/context/annotation/p4.properties

@@ -1 +1,2 @@
 testbean.name=p4TestBean
+from.p4=p4Value

spring-context/src/test/resources/org/springframework/context/annotation/p5.properties

@@ -0,0 +1,2 @@
+testbean.name=p5TestBean
+from.p5=p5Value