Reject use of component scan with REGISTER_BEAN condition

This commit introduce a change of behaviour when component scan is used
with conditions. Previously, any condition in the REGISTER_BEAN phase
were ignored and the scan was applied regardless of the outcome of
those conditions. This is because REGISTER_BEAN condition evaluation
happens later in the bean factory preparation.

Rather than ignoring those conditions, this commit fails fast when it
detects such use case. Code will have to be adapted accordingly.

Closes gh-23206

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -90,16 +90,7 @@ class ConditionEvaluator {
 			return shouldSkip(metadata, ConfigurationPhase.REGISTER_BEAN);
 		}
 
-		List<Condition> conditions = new ArrayList<>();
-		for (String[] conditionClasses : getConditionClasses(metadata)) {
-			for (String conditionClass : conditionClasses) {
-				Condition condition = getCondition(conditionClass, this.context.getClassLoader());
-				conditions.add(condition);
-			}
-		}
-
-		AnnotationAwareOrderComparator.sort(conditions);
-
+		List<Condition> conditions = collectConditions(metadata);
 		for (Condition condition : conditions) {
 			ConfigurationPhase requiredPhase = null;
 			if (condition instanceof ConfigurationCondition configurationCondition) {
@@ -113,6 +104,28 @@ class ConditionEvaluator {
 		return false;
 	}
 
+	/**
+	 * Return the {@linkplain Condition conditions} that should be applied when
+	 * considering the given annotated type.
+	 * @param metadata the metadata of the annotated type
+	 * @return the ordered list of conditions for that type
+	 */
+	List<Condition> collectConditions(@Nullable AnnotatedTypeMetadata metadata) {
+		if (metadata == null || !metadata.isAnnotated(Conditional.class.getName())) {
+			return Collections.emptyList();
+		}
+
+		List<Condition> conditions = new ArrayList<>();
+		for (String[] conditionClasses : getConditionClasses(metadata)) {
+			for (String conditionClass : conditionClasses) {
+				Condition condition = getCondition(conditionClass, this.context.getClassLoader());
+				conditions.add(condition);
+			}
+		}
+		AnnotationAwareOrderComparator.sort(conditions);
+		return conditions;
+	}
+
 	@SuppressWarnings("unchecked")
 	private List<String[]> getConditionClasses(AnnotatedTypeMetadata metadata) {
 		MultiValueMap<String, Object> attributes = metadata.getAllAnnotationAttributes(Conditional.class.getName(), true);

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

@@ -49,6 +49,7 @@ import org.springframework.beans.factory.support.AbstractBeanDefinition;
 import org.springframework.beans.factory.support.BeanDefinitionReader;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.support.BeanNameGenerator;
+import org.springframework.context.ApplicationContextException;
 import org.springframework.context.annotation.ConfigurationCondition.ConfigurationPhase;
 import org.springframework.context.annotation.DeferredImportSelector.Group;
 import org.springframework.core.OrderComparator;
@@ -103,6 +104,10 @@ class ConfigurationClassParser {
 	private static final Predicate<String> DEFAULT_EXCLUSION_FILTER = className ->
 			(className.startsWith("java.lang.annotation.") || className.startsWith("org.springframework.stereotype."));
 
+	private static final Predicate<Condition> REGISTER_BEAN_CONDITION_FILTER = condition ->
+			(condition instanceof ConfigurationCondition configurationCondition
+					&& ConfigurationPhase.REGISTER_BEAN.equals(configurationCondition.getConfigurationPhase()));
+
 	private static final Comparator<DeferredImportSelectorHolder> DEFERRED_IMPORT_COMPARATOR =
 			(o1, o2) -> AnnotationAwareOrderComparator.INSTANCE.compare(o1.getImportSelector(), o2.getImportSelector());
 
@@ -315,6 +320,11 @@ class ConfigurationClassParser {
 		}
 
 		if (!componentScans.isEmpty()) {
+			List<Condition> registerBeanConditions = collectRegisterBeanConditions(configClass);
+			if (!registerBeanConditions.isEmpty()) {
+				throw new ApplicationContextException(
+						"Component scan could not be used with conditions in REGISTER_BEAN phase: " + registerBeanConditions);
+			}
 			for (AnnotationAttributes componentScan : componentScans) {
 				// The config class is annotated with @ComponentScan -> perform the scan immediately
 				Set<BeanDefinitionHolder> scannedBeanDefinitions =
@@ -680,6 +690,27 @@ class ConfigurationClassParser {
 		return new SourceClass(this.metadataReaderFactory.getMetadataReader(className));
 	}
 
+	private List<Condition> collectRegisterBeanConditions(ConfigurationClass configurationClass) {
+		AnnotationMetadata metadata = configurationClass.getMetadata();
+		List<Condition> allConditions = new ArrayList<>(this.conditionEvaluator.collectConditions(metadata));
+		ConfigurationClass enclosingConfigurationClass = getEnclosingConfigurationClass(configurationClass);
+		if (enclosingConfigurationClass != null) {
+			allConditions.addAll(this.conditionEvaluator.collectConditions(enclosingConfigurationClass.getMetadata()));
+		}
+		return allConditions.stream().filter(REGISTER_BEAN_CONDITION_FILTER).toList();
+	}
+
+	@Nullable
+	private ConfigurationClass getEnclosingConfigurationClass(ConfigurationClass configurationClass) {
+		String enclosingClassName = configurationClass.getMetadata().getEnclosingClassName();
+		if (enclosingClassName != null) {
+			return configurationClass.getImportedBy().stream()
+					.filter(candidate -> enclosingClassName.equals(candidate.getMetadata().getClassName()))
+					.findFirst().orElse(null);
+		}
+		return null;
+	}
+
 
 	@SuppressWarnings("serial")
 	private class ImportStack extends ArrayDeque<ConfigurationClass> implements ImportRegistry {