Consider wildcard type without bounds as eligible for fallback match too

Issue: SPR-11250

spring-context/src/test/java/org/springframework/context/annotation/ConfigurationClassPostProcessorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2014 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.
@@ -254,7 +254,34 @@ public class ConfigurationClassPostProcessorTests {
 		ConfigurationClassPostProcessor pp = new ConfigurationClassPostProcessor();
 		pp.postProcessBeanFactory(beanFactory);
 
-		assertSame(beanFactory.getBean("repo"), beanFactory.getBean("repoConsumer"));
+		assertSame(beanFactory.getBean("rawRepo"), beanFactory.getBean("repoConsumer"));
+	}
+
+	@Test
+	public void testGenericsBasedInjectionWithWildcardMatch() {
+		beanFactory.registerBeanDefinition("configClass", new RootBeanDefinition(WildcardMatchingConfiguration.class));
+		ConfigurationClassPostProcessor pp = new ConfigurationClassPostProcessor();
+		pp.postProcessBeanFactory(beanFactory);
+
+		assertSame(beanFactory.getBean("genericRepo"), beanFactory.getBean("repoConsumer"));
+	}
+
+	@Test
+	public void testGenericsBasedInjectionWithWildcardWithExtendsMatch() {
+		beanFactory.registerBeanDefinition("configClass", new RootBeanDefinition(WildcardWithExtendsConfiguration.class));
+		ConfigurationClassPostProcessor pp = new ConfigurationClassPostProcessor();
+		pp.postProcessBeanFactory(beanFactory);
+
+		assertSame(beanFactory.getBean("stringRepo"), beanFactory.getBean("repoConsumer"));
+	}
+
+	@Test
+	public void testGenericsBasedInjectionWithWildcardWithGenericExtendsMatch() {
+		beanFactory.registerBeanDefinition("configClass", new RootBeanDefinition(WildcardWithGenericExtendsConfiguration.class));
+		ConfigurationClassPostProcessor pp = new ConfigurationClassPostProcessor();
+		pp.postProcessBeanFactory(beanFactory);
+
+		assertSame(beanFactory.getBean("genericRepo"), beanFactory.getBean("repoConsumer"));
 	}
 
 
@@ -362,6 +389,16 @@ public class ConfigurationClassPostProcessorTests {
 				}
 			};
 		}
+
+		@Bean
+		public Repository<?> genericRepo() {
+			return new Repository<Object>() {
+				@Override
+				public String toString() {
+					return "Repository<Object>";
+				}
+			};
+		}
 	}
 
 
@@ -387,6 +424,16 @@ public class ConfigurationClassPostProcessorTests {
 				}
 			};
 		}
+
+		@Bean @Scope("prototype")
+		public Repository genericRepo() {
+			return new Repository<Object>() {
+				@Override
+				public String toString() {
+					return "Repository<Object>";
+				}
+			};
+		}
 	}
 
 
@@ -461,7 +508,22 @@ public class ConfigurationClassPostProcessorTests {
 	public static class RawMatchingConfiguration {
 
 		@Bean
-		public Repository repo() {
+		public Repository rawRepo() {
+			return new Repository();
+		}
+
+		@Bean
+		public Object repoConsumer(Repository<String> repo) {
+			return repo;
+		}
+	}
+
+
+	@Configuration
+	public static class WildcardMatchingConfiguration {
+
+		@Bean
+		public Repository<?> genericRepo() {
 			return new Repository();
 		}
 
@@ -471,4 +533,44 @@ public class ConfigurationClassPostProcessorTests {
 		}
 	}
 
+
+	@Configuration
+	public static class WildcardWithExtendsConfiguration {
+
+		@Bean
+		public Repository<? extends String> stringRepo() {
+			return new Repository<String>();
+		}
+
+		@Bean
+		public Repository<? extends Number> numberRepo() {
+			return new Repository<Number>();
+		}
+
+		@Bean
+		public Object repoConsumer(Repository<? extends String> repo) {
+			return repo;
+		}
+	}
+
+
+	@Configuration
+	public static class WildcardWithGenericExtendsConfiguration {
+
+		@Bean
+		public Repository<? extends Object> genericRepo() {
+			return new Repository<String>();
+		}
+
+		@Bean
+		public Repository<? extends Number> numberRepo() {
+			return new Repository<Number>();
+		}
+
+		@Bean
+		public Object repoConsumer(Repository<String> repo) {
+			return repo;
+		}
+	}
+
 }

spring-core/src/main/java/org/springframework/core/ResolvableType.java

@@ -399,7 +399,7 @@ public final class ResolvableType implements Serializable {
 		}
 		ResolvableType[] generics = getGenerics();
 		for (ResolvableType generic : generics) {
-			if (generic.isUnresolvableTypeVariable()) {
+			if (generic.isUnresolvableTypeVariable() || generic.isWildcardWithoutBounds()) {
 				return true;
 			}
 		}
@@ -435,6 +435,23 @@ public final class ResolvableType implements Serializable {
 		return false;
 	}
 
+	/**
+	 * Determine whether the underlying type represents a wildcard
+	 * without specific bounds (i.e., equal to {@code ? extends Object}).
+	 */
+	private boolean isWildcardWithoutBounds() {
+		if (this.type instanceof WildcardType) {
+			WildcardType wt = (WildcardType) this.type;
+			if (wt.getLowerBounds().length == 0) {
+				Type[] upperBounds = wt.getUpperBounds();
+				if (upperBounds.length == 0 || (upperBounds.length == 1 && Object.class.equals(upperBounds[0]))) {
+					return true;
+				}
+			}
+		}
+		return false;
+	}
+
 	/**
 	 * Return a {@link ResolvableType} for the specified nesting level. See
 	 * {@link #getNested(int, Map)} for details.