BeanWrapper does not attempt to populate Map values on access (just auto-grows Map itself)

org.springframework.beans/src/main/java/org/springframework/beans/BeanWrapperImpl.java

@@ -586,18 +586,22 @@ public class BeanWrapperImpl extends AbstractPropertyAccessor implements BeanWra
 		PropertyTokenHolder tokens = new PropertyTokenHolder();
 		tokens.actualName = propertyName;
 		tokens.canonicalName = propertyName;
-		setPropertyValue(tokens, createDefaultPropertyValue(tokens));
-		return getPropertyValue(tokens);
+		return setDefaultValue(tokens);
 	}
 
 	private Object setDefaultValue(PropertyTokenHolder tokens) {
-		setPropertyValue(tokens, createDefaultPropertyValue(tokens));
-		return getPropertyValue(tokens);
+		PropertyValue pv = createDefaultPropertyValue(tokens);
+		setPropertyValue(tokens, pv);
+		return pv.getValue();
 	}
 	
 	private PropertyValue createDefaultPropertyValue(PropertyTokenHolder tokens) {
-		PropertyDescriptor pd = getCachedIntrospectionResults().getPropertyDescriptor(tokens.actualName);
-		Object defaultValue = newValue(pd.getPropertyType(), tokens.canonicalName);
+		Class type = getPropertyType(tokens.canonicalName);
+		if (type == null) {
+			throw new NullValueInNestedPathException(getRootClass(), this.nestedPath + tokens.canonicalName,
+					"Could not determine property type for auto-growing a default value");
+		}
+		Object defaultValue = newValue(type, tokens.canonicalName);
 		return new PropertyValue(tokens.canonicalName, defaultValue);
 	}
 	
@@ -791,9 +795,6 @@ public class BeanWrapperImpl extends AbstractPropertyAccessor implements BeanWra
 						// must not kick in for map keys but rather only for map values.
 						Object convertedMapKey = convertIfNecessary(null, null, key, mapKeyType,
 								new PropertyTypeDescriptor(pd, new MethodParameter(pd.getReadMethod(), -1), mapKeyType));
-						// Pass full property name and old value in here, since we want full
-						// conversion ability for map values.
-						growMapIfNecessary(map, convertedMapKey, indexedPropertyName, pd, i + 1);
 						value = map.get(convertedMapKey);
 					}
 					else {
@@ -865,21 +866,6 @@ public class BeanWrapperImpl extends AbstractPropertyAccessor implements BeanWra
 		}
 	}
 
-	@SuppressWarnings("unchecked")
-	private void growMapIfNecessary(
-			Map map, Object key, String name, PropertyDescriptor pd, int nestingLevel) {
-
-		if (!this.autoGrowNestedPaths) {
-			return;
-		}
-		if (!map.containsKey(key)) {
-			Class valueType = GenericCollectionTypeResolver.getMapValueReturnType(pd.getReadMethod(), nestingLevel);
-			if (valueType != null) {
-				map.put(key, newValue(valueType, name));
-			}
-		}
-	}
-
 	@Override
 	public void setPropertyValue(String propertyName, Object value) throws BeansException {
 		BeanWrapperImpl nestedBw;

org.springframework.beans/src/test/java/org/springframework/beans/BeanWrapperAutoGrowingTests.java

@@ -129,17 +129,10 @@ public class BeanWrapperAutoGrowingTests {
 		wrapper.getPropertyValue("listNotParameterized[0]");
 	}
 
-	@Test
-	public void getPropertyValueAutoGrowMap() {
-		assertNotNull(wrapper.getPropertyValue("map[A]"));
-		assertEquals(1, bean.getMap().size());
-		assertTrue(bean.getMap().get("A") instanceof Bean);
-	}
-
 	@Test
 	public void setPropertyValueAutoGrowMap() {
-		wrapper.setPropertyValue("map[A].prop", "test");
-		assertEquals("test", bean.getMap().get("A").getProp());
+		wrapper.setPropertyValue("map[A]", new Bean());
+		assertTrue(bean.getMap().get("A") instanceof Bean);
 	}