Support non-public BeanOverrideProcessors in the TestContext framework

Closes gh-32485

Author: sbrannen

spring-test/src/main/java/org/springframework/test/context/bean/override/BeanOverrideParser.java

@@ -17,21 +17,17 @@
 package org.springframework.test.context.bean.override;
 
 import java.lang.annotation.Annotation;
-import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
-import java.lang.reflect.InvocationTargetException;
 import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 
-import org.springframework.beans.factory.support.BeanDefinitionValidationException;
+import org.springframework.beans.BeanUtils;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.annotation.MergedAnnotation;
 import org.springframework.core.annotation.MergedAnnotations;
-import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
-import org.springframework.util.ClassUtils;
 import org.springframework.util.ReflectionUtils;
 
 import static org.springframework.core.annotation.MergedAnnotations.SearchStrategy.DIRECT;
@@ -41,6 +37,7 @@
  * on fields of a given class and creates {@link OverrideMetadata} accordingly.
  *
  * @author Simon Baslé
+ * @author Sam Brannen
  * @since 6.2
  */
 class BeanOverrideParser {
@@ -102,41 +99,21 @@ private void parseField(Field field, Class<?> source) {
 				.map(mergedAnnotation -> {
 					MergedAnnotation<?> metaSource = mergedAnnotation.getMetaSource();
 					Assert.notNull(metaSource, "@BeanOverride annotation must be meta-present");
-					return new AnnotationPair(metaSource.synthesize(), mergedAnnotation);
+					return new AnnotationPair(metaSource.synthesize(), mergedAnnotation.synthesize());
 				})
 				.forEach(pair -> {
-					BeanOverride beanOverride = pair.mergedAnnotation().synthesize();
-					BeanOverrideProcessor processor = getProcessorInstance(beanOverride.value());
-					if (processor == null) {
-						return;
-					}
-					ResolvableType typeToOverride = processor.getOrDeduceType(field, pair.annotation(), source);
+					BeanOverrideProcessor processor = BeanUtils.instantiateClass(pair.beanOverride.value());
+					ResolvableType typeToOverride = processor.getOrDeduceType(field, pair.composedAnnotation, source);
 
 					Assert.state(overrideAnnotationFound.compareAndSet(false, true),
 							() -> "Multiple @BeanOverride annotations found on field: " + field);
-					OverrideMetadata metadata = processor.createMetadata(field, pair.annotation(), typeToOverride);
+					OverrideMetadata metadata = processor.createMetadata(field, pair.composedAnnotation, typeToOverride);
 					boolean isNewDefinition = this.parsedMetadata.add(metadata);
 					Assert.state(isNewDefinition, () -> "Duplicate " + metadata.getBeanOverrideDescription() +
 								" OverrideMetadata: " + metadata);
 				});
 	}
 
-	@Nullable
-	private BeanOverrideProcessor getProcessorInstance(Class<? extends BeanOverrideProcessor> processorClass) {
-		Constructor<? extends BeanOverrideProcessor> constructor = ClassUtils.getConstructorIfAvailable(processorClass);
-		if (constructor != null) {
-			try {
-				ReflectionUtils.makeAccessible(constructor);
-				return constructor.newInstance();
-			}
-			catch (InstantiationException | IllegalAccessException | InvocationTargetException ex) {
-				throw new BeanDefinitionValidationException(
-						"Failed to instantiate BeanOverrideProcessor of type " + processorClass.getName(), ex);
-			}
-		}
-		return null;
-	}
-
-	private record AnnotationPair(Annotation annotation, MergedAnnotation<BeanOverride> mergedAnnotation) {}
+	private record AnnotationPair(Annotation composedAnnotation, BeanOverride beanOverride) {}
 
 }

spring-test/src/test/java/org/springframework/test/context/bean/override/BeanOverrideParserTests.java

@@ -26,7 +26,6 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatRuntimeException;
-import static org.springframework.test.context.bean.override.example.ExampleBeanOverrideProcessor.DUPLICATE_TRIGGER;
 
 /**
  * Unit tests for {@link BeanOverrideParser}.
@@ -35,6 +34,9 @@
  */
 class BeanOverrideParserTests {
 
+	// Copy of ExampleBeanOverrideProcessor.DUPLICATE_TRIGGER which is package-private.
+	private static final String DUPLICATE_TRIGGER = "DUPLICATE";
+
 	private final BeanOverrideParser parser = new BeanOverrideParser();
 
 

spring-test/src/test/java/org/springframework/test/context/bean/override/example/ExampleBeanOverrideProcessor.java

@@ -23,7 +23,10 @@
 import org.springframework.test.context.bean.override.BeanOverrideProcessor;
 import org.springframework.test.context.bean.override.OverrideMetadata;
 
-public class ExampleBeanOverrideProcessor implements BeanOverrideProcessor {
+// Intentionally NOT public
+class ExampleBeanOverrideProcessor implements BeanOverrideProcessor {
+
+	static final String DUPLICATE_TRIGGER = "DUPLICATE";
 
 	private static final TestOverrideMetadata CONSTANT = new TestOverrideMetadata() {
 		@Override
@@ -32,8 +35,6 @@ public String toString() {
 		}
 	};
 
-	public static final String DUPLICATE_TRIGGER = "CONSTANT";
-
 	@Override
 	public OverrideMetadata createMetadata(Field field, Annotation overrideAnnotation, ResolvableType typeToOverride) {
 		if (!(overrideAnnotation instanceof ExampleBeanOverrideAnnotation annotation)) {

spring-test/src/test/java/org/springframework/test/context/bean/override/example/TestOverrideMetadata.java

@@ -32,7 +32,7 @@
 
 import static org.springframework.test.context.bean.override.example.ExampleBeanOverrideAnnotation.DEFAULT_VALUE;
 
-public class TestOverrideMetadata extends OverrideMetadata {
+class TestOverrideMetadata extends OverrideMetadata {
 
 	@Nullable
 	private final Method method;