Support repeatable annotation containers with multiple attributes

Prior to this commit, there was a bug in the implementation of
StandardRepeatableContainers.computeRepeatedAnnotationsMethod() which
has existed since Spring Framework 5.2 (when
StandardRepeatableContainers was introduced). Specifically,
StandardRepeatableContainers ignored any repeatable container
annotation if it declared attributes other than `value()`. However,
Java permits any number of attributes in a repeatable container
annotation.

In addition, the changes made in conjunction with spring-projectsgh-20279 made the bug
in StandardRepeatableContainers apparent when using the
getMergedRepeatableAnnotations() or findMergedRepeatableAnnotations()
method in AnnotatedElementUtils, resulting in regressions for the
behavior of those two methods.

This commit fixes the regressions and bug by altering the logic in
StandardRepeatableContainers.computeRepeatedAnnotationsMethod() so that
it explicitly looks for the `value()` method and ignores any other
methods declared in a repeatable container annotation candidate.

Closes spring-projectsgh-29685

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

@@ -166,8 +166,8 @@ private static Method getRepeatedAnnotationsMethod(Class<? extends Annotation> a
 
 		private static Object computeRepeatedAnnotationsMethod(Class<? extends Annotation> annotationType) {
 			AttributeMethods methods = AttributeMethods.forAnnotationType(annotationType);
-			if (methods.hasOnlyValueAttribute()) {
-				Method method = methods.get(0);
+			Method method = methods.get(MergedAnnotation.VALUE);
+			if (method != null) {
 				Class<?> returnType = method.getReturnType();
 				if (returnType.isArray()) {
 					Class<?> componentType = returnType.getComponentType();

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

@@ -20,6 +20,7 @@
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Inherited;
+import java.lang.annotation.Repeatable;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
@@ -77,6 +78,7 @@
  * @see AnnotationUtilsTests
  * @see MultipleComposedAnnotationsOnSingleAnnotatedElementTests
  * @see ComposedRepeatableAnnotationsTests
+ * @see NestedRepeatableAnnotationsTests
  */
 class AnnotatedElementUtilsTests {
 
@@ -908,6 +910,31 @@ void getMergedAnnotationOnThreeDeepMetaWithValue() {
 		assertThat(annotation.value()).containsExactly("FromValueAttributeMeta");
 	}
 
+	/**
+	 * @since 5.3.25
+	 */
+	@Test // gh-29685
+	void getMergedRepeatableAnnotationsWithContainerWithMultipleAttributes() {
+		Set<StandardRepeatableWithContainerWithMultipleAttributes> repeatableAnnotations =
+				AnnotatedElementUtils.getMergedRepeatableAnnotations(
+						StandardRepeatablesWithContainerWithMultipleAttributesTestCase.class,
+						StandardRepeatableWithContainerWithMultipleAttributes.class);
+		assertThat(repeatableAnnotations).map(StandardRepeatableWithContainerWithMultipleAttributes::value)
+				.containsExactly("a", "b");
+	}
+
+	/**
+	 * @since 5.3.25
+	 */
+	@Test // gh-29685
+	void findMergedRepeatableAnnotationsWithContainerWithMultipleAttributes() {
+		Set<StandardRepeatableWithContainerWithMultipleAttributes> repeatableAnnotations =
+				AnnotatedElementUtils.findMergedRepeatableAnnotations(
+						StandardRepeatablesWithContainerWithMultipleAttributesTestCase.class,
+						StandardRepeatableWithContainerWithMultipleAttributes.class);
+		assertThat(repeatableAnnotations).map(StandardRepeatableWithContainerWithMultipleAttributes::value)
+				.containsExactly("a", "b");
+	}
 
 	// -------------------------------------------------------------------------
 
@@ -1567,4 +1594,24 @@ class ForAnnotationsClass {
 	static class ValueAttributeMetaMetaClass {
 	}
 
+	@Retention(RetentionPolicy.RUNTIME)
+	@interface StandardContainerWithMultipleAttributes {
+
+		StandardRepeatableWithContainerWithMultipleAttributes[] value();
+
+		String name() default "";
+	}
+
+	@Retention(RetentionPolicy.RUNTIME)
+	@Repeatable(StandardContainerWithMultipleAttributes.class)
+	@interface StandardRepeatableWithContainerWithMultipleAttributes {
+
+		String value() default "";
+	}
+
+	@StandardRepeatableWithContainerWithMultipleAttributes("a")
+	@StandardRepeatableWithContainerWithMultipleAttributes("b")
+	static class StandardRepeatablesWithContainerWithMultipleAttributesTestCase {
+	}
+
 }

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

@@ -67,6 +67,15 @@ void standardRepeatablesWhenContainerReturnsRepeats() {
 				StandardRepeatablesTestCase.class, StandardContainer.class);
 			assertThat(values).containsExactly("a", "b");
 		}
+
+		@Test
+		void standardRepeatablesWithContainerWithMultipleAttributes() {
+			Object[] values = findRepeatedAnnotationValues(RepeatableContainers.standardRepeatables(),
+				StandardRepeatablesWithContainerWithMultipleAttributesTestCase.class,
+				StandardContainerWithMultipleAttributes.class);
+			assertThat(values).containsExactly("a", "b");
+		}
+
 	}
 
 	@Nested
@@ -247,6 +256,26 @@ static class SingleStandardRepeatableTestCase {
 	static class StandardRepeatablesTestCase {
 	}
 
+	@Retention(RetentionPolicy.RUNTIME)
+	@interface StandardContainerWithMultipleAttributes {
+
+		StandardRepeatableWithContainerWithMultipleAttributes[] value();
+
+		String name() default "";
+	}
+
+	@Retention(RetentionPolicy.RUNTIME)
+	@Repeatable(StandardContainerWithMultipleAttributes.class)
+	@interface StandardRepeatableWithContainerWithMultipleAttributes {
+
+		String value() default "";
+	}
+
+	@StandardRepeatableWithContainerWithMultipleAttributes("a")
+	@StandardRepeatableWithContainerWithMultipleAttributes("b")
+	static class StandardRepeatablesWithContainerWithMultipleAttributesTestCase {
+	}
+
 	@ExplicitContainer({ @ExplicitRepeatable("a"), @ExplicitRepeatable("b") })
 	static class ExplicitRepeatablesTestCase {
 	}