TypeDescriptor's nested type traversal leniently returns null in case of unresolvable nested type

Issue: SPR-11898
(cherry picked from commit d663580)

Author: jhoeller

spring-beans/src/test/java/org/springframework/beans/BeanWrapperGenericsTests.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.
@@ -28,7 +28,6 @@
 import java.util.Map;
 import java.util.Set;
 
-import static org.junit.Assert.*;
 import org.junit.Test;
 
 import org.springframework.beans.propertyeditors.CustomNumberEditor;
@@ -40,6 +39,8 @@
 import org.springframework.tests.sample.beans.GenericSetOfIntegerBean;
 import org.springframework.tests.sample.beans.TestBean;
 
+import static org.junit.Assert.*;
+
 /**
  * @author Juergen Hoeller
  * @author Chris Beams
@@ -485,6 +486,29 @@ public void testSettingLongPropertyWithGenericInterface() {
 		assertEquals(new Long(10), bean.getId());
 	}
 
+	@Test
+	public void testUntypedPropertyWithMapAtRuntime() {
+		class Holder<D> {
+			private final D data;
+			public Holder(D data) {
+				this.data = data;
+			}
+			public D getData() {
+				return this.data;
+			}
+		}
+
+		Map<String, Object> data = new HashMap<String, Object>();
+		data.put("x", "y");
+		Holder<Map<String, Object>> context = new Holder<Map<String,Object>>(data);
+
+		BeanWrapper bw = PropertyAccessorFactory.forBeanPropertyAccess(context);
+		assertEquals("y", bw.getPropertyValue("data['x']"));
+
+		bw.setPropertyValue("data['message']", "it works!");
+		assertEquals(data.get("message"), "it works!");
+	}
+
 
 	private static abstract class BaseGenericCollectionBean {
 

spring-core/src/main/java/org/springframework/core/convert/TypeDescriptor.java

@@ -701,8 +701,7 @@ private static TypeDescriptor nested(TypeDescriptor typeDescriptor, int nestingL
 			}
 		}
 		if (nested == ResolvableType.NONE) {
-			throw new IllegalStateException(
-					"Unable to obtain nested generic from " + typeDescriptor + " at level " + nestingLevel);
+			return null;
 		}
 		return getRelatedIfResolvable(typeDescriptor, nested);
 	}

spring-core/src/test/java/org/springframework/core/convert/TypeDescriptorTests.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.
@@ -36,6 +36,7 @@
 import java.util.Set;
 
 import org.junit.Test;
+
 import org.springframework.core.MethodParameter;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
@@ -69,6 +70,7 @@ public class TypeDescriptorTests {
 
 	public Map<String, List<Integer>> nestedMapField = new HashMap<String, List<Integer>>();
 
+
 	@Test
 	public void parameterPrimitive() throws Exception {
 		TypeDescriptor desc = new TypeDescriptor(new MethodParameter(getClass().getMethod("testParameterPrimitive", int.class), 0));
@@ -555,15 +557,16 @@ public void nestedMethodParameterNot1NestedLevel() throws Exception {
 		TypeDescriptor.nested(new MethodParameter(getClass().getMethod("test4", List.class), 0, 2), 2);
 	}
 
-	@Test(expected=IllegalStateException.class)
+	@Test
 	public void nestedTooManyLevels() throws Exception {
 		TypeDescriptor t1 = TypeDescriptor.nested(new MethodParameter(getClass().getMethod("test4", List.class), 0), 3);
-		assertEquals(String.class, t1.getType());
+		assertNull(t1);
 	}
 
-	@Test(expected=IllegalStateException.class)
+	@Test
 	public void nestedMethodParameterTypeNotNestable() throws Exception {
-		TypeDescriptor.nested(new MethodParameter(getClass().getMethod("test5", String.class), 0), 2);
+		TypeDescriptor t1 = TypeDescriptor.nested(new MethodParameter(getClass().getMethod("test5", String.class), 0), 2);
+		assertNull(t1);
 	}
 
 	@Test(expected=IllegalArgumentException.class)
@@ -941,4 +944,5 @@ public void getSource() throws Exception {
 		assertThat(new TypeDescriptor(methodParameter).getSource(), equalTo((Object) methodParameter));
 		assertThat(TypeDescriptor.valueOf(Integer.class).getSource(), equalTo((Object) Integer.class));
 	}
+
 }