BeanMethodInterceptor does not pass on null arguments for singleton beans

Issue: SPR-13887

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -592,17 +592,23 @@ public class ConfigurationClassPostProcessorTests {
 	}
 
 	@Test
-	public void testPrototypeArgumentsThroughBeanMethodCall() {
+	public void testPrototypeArgumentThroughBeanMethodCall() {
 		ApplicationContext ctx = new AnnotationConfigApplicationContext(BeanArgumentConfigWithPrototype.class);
 		ctx.getBean(FooFactory.class).createFoo(new BarArgument());
 	}
 
 	@Test
-	public void testSingletonArgumentsThroughBeanMethodCall() {
+	public void testSingletonArgumentThroughBeanMethodCall() {
 		ApplicationContext ctx = new AnnotationConfigApplicationContext(BeanArgumentConfigWithSingleton.class);
 		ctx.getBean(FooFactory.class).createFoo(new BarArgument());
 	}
 
+	@Test
+	public void testNullArgumentThroughBeanMethodCall() {
+		ApplicationContext ctx = new AnnotationConfigApplicationContext(BeanArgumentConfigWithNull.class);
+		ctx.getBean("aFoo");
+	}
+
 
 	// -------------------------------------------------------------------------
 
@@ -1137,7 +1143,7 @@ public class ConfigurationClassPostProcessorTests {
 
 		@Bean
 		@Scope("prototype")
-		public DependingFoo foo(final BarArgument bar) {
+		public DependingFoo foo(BarArgument bar) {
 			return new DependingFoo(bar);
 		}
 
@@ -1145,7 +1151,7 @@ public class ConfigurationClassPostProcessorTests {
 		public FooFactory fooFactory() {
 			return new FooFactory() {
 				@Override
-				public DependingFoo createFoo(final BarArgument bar) {
+				public DependingFoo createFoo(BarArgument bar) {
 					return foo(bar);
 				}
 			};
@@ -1156,7 +1162,7 @@ public class ConfigurationClassPostProcessorTests {
 	static class BeanArgumentConfigWithSingleton {
 
 		@Bean @Lazy
-		public DependingFoo foo(final BarArgument bar) {
+		public DependingFoo foo(BarArgument bar) {
 			return new DependingFoo(bar);
 		}
 
@@ -1164,19 +1170,39 @@ public class ConfigurationClassPostProcessorTests {
 		public FooFactory fooFactory() {
 			return new FooFactory() {
 				@Override
-				public DependingFoo createFoo(final BarArgument bar) {
+				public DependingFoo createFoo(BarArgument bar) {
 					return foo(bar);
 				}
 			};
 		}
 	}
 
+	@Configuration
+	static class BeanArgumentConfigWithNull {
+
+		@Bean
+		public DependingFoo aFoo() {
+			return foo(null);
+		}
+
+		@Bean @Lazy
+		public DependingFoo foo(BarArgument bar) {
+			return new DependingFoo(bar);
+		}
+
+		@Bean
+		public BarArgument bar() {
+			return new BarArgument();
+		}
+	}
+
 	static class BarArgument {
 	}
 
 	static class DependingFoo {
 
 		DependingFoo(BarArgument bar) {
+			Assert.notNull(bar);
 		}
 	}