Prevent incorrect ImportAware metdata injection

Update ImportRegistry to track all import registrations that occur
against an importing class (rather than just keeping the last). In
addition, prune imported classes from the registry when a configuration
class is removed during the REGISTER_BEAN ConfigurationPhase.

This update prevents incorrect metadata from being injected into an
ImportAware class which is imported twice by different configurations
classes (when one of the configuration classes will be ultimately skipped
due to a @Condition).

Issue: SPR-12128

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

@@ -44,6 +44,7 @@ import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.support.BeanNameGenerator;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
+import org.springframework.context.annotation.ConfigurationClassParser.ImportRegistry;
 import org.springframework.context.annotation.ConfigurationCondition.ConfigurationPhase;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.env.Environment;
@@ -86,6 +87,8 @@ class ConfigurationClassBeanDefinitionReader {
 
 	private final BeanNameGenerator importBeanNameGenerator;
 
+	private final ImportRegistry importRegistry;
+
 	private final ConditionEvaluator conditionEvaluator;
 
 
@@ -95,7 +98,8 @@ class ConfigurationClassBeanDefinitionReader {
 	 */
 	public ConfigurationClassBeanDefinitionReader(BeanDefinitionRegistry registry, SourceExtractor sourceExtractor,
 			ProblemReporter problemReporter, MetadataReaderFactory metadataReaderFactory,
-			ResourceLoader resourceLoader, Environment environment, BeanNameGenerator importBeanNameGenerator) {
+			ResourceLoader resourceLoader, Environment environment, BeanNameGenerator importBeanNameGenerator,
+			ImportRegistry importRegistry) {
 
 		this.registry = registry;
 		this.sourceExtractor = sourceExtractor;
@@ -104,6 +108,7 @@ class ConfigurationClassBeanDefinitionReader {
 		this.resourceLoader = resourceLoader;
 		this.environment = environment;
 		this.importBeanNameGenerator = importBeanNameGenerator;
+		this.importRegistry = importRegistry;
 		this.conditionEvaluator = new ConditionEvaluator(registry, environment, resourceLoader);
 	}
 
@@ -128,6 +133,7 @@ class ConfigurationClassBeanDefinitionReader {
 
 		if (trackedConditionEvaluator.shouldSkip(configClass)) {
 			removeBeanDefinition(configClass);
+			importRegistry.removeImportingClassFor(configClass.getMetadata().getClassName());
 			return;
 		}
 

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

@@ -72,6 +72,8 @@ import org.springframework.core.type.classreading.MetadataReader;
 import org.springframework.core.type.classreading.MetadataReaderFactory;
 import org.springframework.core.type.filter.AssignableTypeFilter;
 import org.springframework.util.Assert;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
 import org.springframework.util.StringUtils;
 
 /**
@@ -470,10 +472,8 @@ class ConfigurationClassParser {
 					}
 					else {
 						// Candidate class not an ImportSelector or ImportBeanDefinitionRegistrar -> process it as a @Configuration class
-						if (!this.conditionEvaluator.shouldSkip(configClass.getMetadata(), ConfigurationPhase.REGISTER_BEAN)) {
-							this.importStack.registerImport(currentSourceClass.getMetadata(), candidate.getMetadata().getClassName());
-							processConfigurationClass(candidate.asConfigClass(configClass));
-						}
+						this.importStack.registerImport(currentSourceClass.getMetadata(), candidate.getMetadata().getClassName());
+						processConfigurationClass(candidate.asConfigClass(configClass));
 					}
 				}
 			}
@@ -591,21 +591,35 @@ class ConfigurationClassParser {
 	interface ImportRegistry {
 
 		AnnotationMetadata getImportingClassFor(String importedClass);
+
+		void removeImportingClassFor(String importedClass);
 	}
 
 
 	@SuppressWarnings("serial")
 	private static class ImportStack extends Stack<ConfigurationClass> implements ImportRegistry {
 
-		private final Map<String, AnnotationMetadata> imports = new HashMap<String, AnnotationMetadata>();
+		private final MultiValueMap<String, AnnotationMetadata> imports = new LinkedMultiValueMap<String, AnnotationMetadata>();
 
 		public void registerImport(AnnotationMetadata importingClass, String importedClass) {
-			this.imports.put(importedClass, importingClass);
+			this.imports.add(importedClass, importingClass);
+		}
+
+		@Override
+		public void removeImportingClassFor(String importedClass) {
+			for (List<AnnotationMetadata> list : this.imports.values()) {
+				for (Iterator<AnnotationMetadata> iterator = list.iterator(); iterator.hasNext();) {
+					if (iterator.next().getClassName().equals(importedClass)) {
+						iterator.remove();
+					}
+				}
+			}
 		}
 
 		@Override
 		public AnnotationMetadata getImportingClassFor(String importedClass) {
-			return this.imports.get(importedClass);
+			List<AnnotationMetadata> list = this.imports.get(importedClass);
+			return (list == null || list.isEmpty() ? null : list.get(list.size() - 1));
 		}
 
 		/**

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

@@ -314,7 +314,7 @@ public class ConfigurationClassPostProcessor implements BeanDefinitionRegistryPo
 			if (this.reader == null) {
 				this.reader = new ConfigurationClassBeanDefinitionReader(registry, this.sourceExtractor,
 						this.problemReporter, this.metadataReaderFactory, this.resourceLoader, this.environment,
-						this.importBeanNameGenerator);
+						this.importBeanNameGenerator, parser.getImportRegistry());
 			}
 			this.reader.loadBeanDefinitions(configClasses);
 			alreadyParsed.addAll(configClasses);

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

@@ -234,7 +234,7 @@ public class ImportAwareTests {
 	}
 
 
-	@Conditional(NeverMatchingCondition.class)
+	@Conditional(OnMissingBeanCondition.class)
 	@EnableSomeConfiguration("foo")
 	@Configuration
 	public static class ConfigurationTwo {
@@ -277,11 +277,12 @@ public class ImportAwareTests {
 	}
 
 
-	private static final class NeverMatchingCondition implements ConfigurationCondition {
+	private static final class OnMissingBeanCondition implements ConfigurationCondition {
 
 		@Override
 		public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
-			return false;
+			return context.getBeanFactory().getBeanNamesForType(MetadataHolder.class,
+					true, false).length == 0;
 		}
 
 		@Override