Generic matching for ObjectProvider stream and empty vararg resolution

Issue: SPR-11419
Issue: SPR-15338

Author: jhoeller

spring-beans/src/main/java/org/springframework/beans/factory/support/ConstructorResolver.java

@@ -17,6 +17,7 @@
 package org.springframework.beans.factory.support;
 
 import java.beans.ConstructorProperties;
+import java.lang.reflect.Array;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Executable;
 import java.lang.reflect.Method;
@@ -824,9 +825,12 @@ protected Object resolveAutowiredArgument(MethodParameter param, String beanName
 		}
 		catch (NoSuchBeanDefinitionException ex) {
 			if (fallback) {
-				// Single constructor or factory method -> let's return an
-				// empty collection for a non-null collection parameter.
-				if (CollectionFactory.isApproximableCollectionType(paramType)) {
+				// Single constructor or factory method -> let's return an empty array/collection
+				// for e.g. a vararg or a non-null List/Set/Map parameter.
+				if (paramType.isArray()) {
+					return Array.newInstance(paramType.getComponentType(), 0);
+				}
+				else if (CollectionFactory.isApproximableCollectionType(paramType)) {
 					return CollectionFactory.createCollection(paramType, 0);
 				}
 				else if (CollectionFactory.isApproximableMapType(paramType)) {

spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultListableBeanFactory.java

@@ -1229,7 +1229,7 @@ private Object resolveMultipleBeans(DependencyDescriptor descriptor, @Nullable S
 
 		if (descriptor.isStreamAccess()) {
 			Map<String, Object> matchingBeans = findAutowireCandidates(beanName, type,
-					new MultiElementDescriptor(descriptor));
+					new MultiElementDescriptor(descriptor, false));
 			if (autowiredBeanNames != null) {
 				autowiredBeanNames.addAll(matchingBeans.keySet());
 			}
@@ -1247,7 +1247,7 @@ else if (type.isArray()) {
 				return null;
 			}
 			Map<String, Object> matchingBeans = findAutowireCandidates(beanName, componentType,
-					new MultiElementDescriptor(descriptor));
+					new MultiElementDescriptor(descriptor, true));
 			if (matchingBeans.isEmpty()) {
 				return null;
 			}
@@ -1267,7 +1267,7 @@ else if (Collection.class.isAssignableFrom(type) && type.isInterface()) {
 				return null;
 			}
 			Map<String, Object> matchingBeans = findAutowireCandidates(beanName, elementType,
-					new MultiElementDescriptor(descriptor));
+					new MultiElementDescriptor(descriptor, true));
 			if (matchingBeans.isEmpty()) {
 				return null;
 			}
@@ -1292,7 +1292,7 @@ else if (Map.class == type) {
 				return null;
 			}
 			Map<String, Object> matchingBeans = findAutowireCandidates(beanName, valueType,
-					new MultiElementDescriptor(descriptor));
+					new MultiElementDescriptor(descriptor, true));
 			if (matchingBeans.isEmpty()) {
 				return null;
 			}
@@ -1716,10 +1716,13 @@ public NestedDependencyDescriptor(DependencyDescriptor original) {
 	/**
 	 * A dependency descriptor marker for multiple elements.
 	 */
-	private static class MultiElementDescriptor extends NestedDependencyDescriptor {
+	private static class MultiElementDescriptor extends DependencyDescriptor {
 
-		public MultiElementDescriptor(DependencyDescriptor original) {
+		public MultiElementDescriptor(DependencyDescriptor original, boolean nested) {
 			super(original);
+			if (nested) {
+				increaseNestingLevel();
+			}
 		}
 	}