Include repeatable annotation container in MergedAnnotations results

A bug has existed in Spring's MergedAnnotations support since it was
introduced in Spring Framework 5.2. Specifically, if the
MergedAnnotations API is used to search for annotations with "standard
repeatable annotation" support enabled (which is the default), it's
possible to search for a repeatable annotation but not for the
repeatable annotation's container annotation.

The reason is that MergedAnnotationFinder.process(Object, int, Object,
Annotation) does not process the container annotation and instead only
processes the "contained" annotations, which prevents a container
annotation from being included in search results.

In #29685, we fixed a bug that prevented the MergedAnnotations support
from recognizing an annotation as a container if the container
annotation declares attributes other than the required `value`
attribute. As a consequence of that bug fix, since Spring Framework
5.3.25, the MergedAnnotations infrastructure considers such an
annotation a container, and due to the aforementioned bug the container
is no longer processed, which results in a regression in behavior for
annotation searches for such a container annotation.

This commit addresses the original bug as well as the regression by
processing container annotations in addition to the contained
repeatable annotations.

See gh-29685
Closes gh-32731

spring-core/src/main/java/org/springframework/core/annotation/TypeMappedAnnotations.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 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.
@@ -418,7 +418,10 @@ final class TypeMappedAnnotations implements MergedAnnotations {
 
 			Annotation[] repeatedAnnotations = repeatableContainers.findRepeatedAnnotations(annotation);
 			if (repeatedAnnotations != null) {
-				return doWithAnnotations(type, aggregateIndex, source, repeatedAnnotations);
+				MergedAnnotation<A> result = doWithAnnotations(type, aggregateIndex, source, repeatedAnnotations);
+				if (result != null) {
+					return result;
+				}
 			}
 			AnnotationTypeMappings mappings = AnnotationTypeMappings.forAnnotationType(
 					annotation.annotationType(), repeatableContainers, annotationFilter);

spring-core/src/test/java/org/springframework/core/annotation/MergedAnnotationsRepeatableAnnotationTests.java

@@ -24,6 +24,7 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 import java.lang.reflect.AnnotatedElement;
+import java.util.Arrays;
 import java.util.Set;
 import java.util.stream.Stream;
 
@@ -168,7 +169,7 @@ class MergedAnnotationsRepeatableAnnotationTests {
 	}
 
 	@Test
-	void typeHierarchyWhenWhenOnSuperclassReturnsAnnotations() {
+	void typeHierarchyWhenOnSuperclassReturnsAnnotations() {
 		Set<PeteRepeat> annotations = getAnnotations(null, PeteRepeat.class,
 				TYPE_HIERARCHY, SubRepeatableClass.class);
 		assertThat(annotations.stream().map(PeteRepeat::value)).containsExactly("A", "B", "C");
@@ -226,6 +227,44 @@ class MergedAnnotationsRepeatableAnnotationTests {
 		assertThat(annotationTypes).containsExactly(WithRepeatedMetaAnnotations.class, Noninherited.class, Noninherited.class);
 	}
 
+	@Test  // gh-32731
+	void searchFindsRepeatableContainerAnnotationAndRepeatedAnnotations() {
+		Class<?> clazz = StandardRepeatablesWithContainerWithMultipleAttributesTestCase.class;
+
+		// NO RepeatableContainers
+		MergedAnnotations mergedAnnotations = MergedAnnotations.from(clazz, TYPE_HIERARCHY, RepeatableContainers.none());
+		ContainerWithMultipleAttributes container = mergedAnnotations
+				.get(ContainerWithMultipleAttributes.class)
+				.synthesize(MergedAnnotation::isPresent).orElse(null);
+		assertThat(container).as("container").isNotNull();
+		assertThat(container.name()).isEqualTo("enigma");
+		RepeatableWithContainerWithMultipleAttributes[] repeatedAnnotations = container.value();
+		assertThat(Arrays.stream(repeatedAnnotations).map(RepeatableWithContainerWithMultipleAttributes::value))
+				.containsExactly("A", "B");
+		Set<RepeatableWithContainerWithMultipleAttributes> set =
+				mergedAnnotations.stream(RepeatableWithContainerWithMultipleAttributes.class)
+				.collect(MergedAnnotationCollectors.toAnnotationSet());
+		// Only finds the locally declared repeated annotation.
+		assertThat(set.stream().map(RepeatableWithContainerWithMultipleAttributes::value))
+				.containsExactly("C");
+
+		// Standard RepeatableContainers
+		mergedAnnotations = MergedAnnotations.from(clazz, TYPE_HIERARCHY, RepeatableContainers.standardRepeatables());
+		container = mergedAnnotations
+				.get(ContainerWithMultipleAttributes.class)
+				.synthesize(MergedAnnotation::isPresent).orElse(null);
+		assertThat(container).as("container").isNotNull();
+		assertThat(container.name()).isEqualTo("enigma");
+		repeatedAnnotations = container.value();
+		assertThat(Arrays.stream(repeatedAnnotations).map(RepeatableWithContainerWithMultipleAttributes::value))
+				.containsExactly("A", "B");
+		set = mergedAnnotations.stream(RepeatableWithContainerWithMultipleAttributes.class)
+				.collect(MergedAnnotationCollectors.toAnnotationSet());
+		// Finds the locally declared repeated annotation plus the 2 in the container.
+		assertThat(set.stream().map(RepeatableWithContainerWithMultipleAttributes::value))
+				.containsExactly("A", "B", "C");
+	}
+
 	private <A extends Annotation> Set<A> getAnnotations(Class<? extends Annotation> container,
 			Class<A> repeatable, SearchStrategy searchStrategy, AnnotatedElement element) {
 
@@ -420,4 +459,27 @@ class MergedAnnotationsRepeatableAnnotationTests {
 	static class WithRepeatedMetaAnnotationsClass {
 	}
 
+	@Retention(RetentionPolicy.RUNTIME)
+	@interface ContainerWithMultipleAttributes {
+
+		RepeatableWithContainerWithMultipleAttributes[] value();
+
+		String name() default "";
+	}
+
+	@Retention(RetentionPolicy.RUNTIME)
+	@Repeatable(ContainerWithMultipleAttributes.class)
+	@interface RepeatableWithContainerWithMultipleAttributes {
+
+		String value() default "";
+	}
+
+	@ContainerWithMultipleAttributes(name = "enigma", value = {
+		@RepeatableWithContainerWithMultipleAttributes("A"),
+		@RepeatableWithContainerWithMultipleAttributes("B")
+	})
+	@RepeatableWithContainerWithMultipleAttributes("C")
+	static class StandardRepeatablesWithContainerWithMultipleAttributesTestCase {
+	}
+
 }