Avoid ResolvableType for simple assignability check in copyProperties

Closes gh-27246

Author: jhoeller

spring-beans/src/main/java/org/springframework/beans/BeanUtils.java

@@ -23,6 +23,7 @@
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
+import java.lang.reflect.Type;
 import java.net.URI;
 import java.net.URL;
 import java.time.temporal.Temporal;
@@ -615,8 +616,8 @@ public static Class<?> findPropertyType(String propertyName, @Nullable Class<?>.
 	 * @return a corresponding MethodParameter object
 	 */
 	public static MethodParameter getWriteMethodParameter(PropertyDescriptor pd) {
-		if (pd instanceof GenericTypeAwarePropertyDescriptor typeAwarePd) {
-			return new MethodParameter(typeAwarePd.getWriteMethodParameter());
+		if (pd instanceof GenericTypeAwarePropertyDescriptor gpd) {
+			return new MethodParameter(gpd.getWriteMethodParameter());
 		}
 		else {
 			Method writeMethod = pd.getWriteMethod();
@@ -787,38 +788,28 @@ private static void copyProperties(Object source, Object target, @Nullable Class
 		if (editable != null) {
 			if (!editable.isInstance(target)) {
 				throw new IllegalArgumentException("Target class [" + target.getClass().getName() +
-						"] not assignable to Editable class [" + editable.getName() + "]");
+						"] not assignable to editable class [" + editable.getName() + "]");
 			}
 			actualEditable = editable;
 		}
 		PropertyDescriptor[] targetPds = getPropertyDescriptors(actualEditable);
 		Set<String> ignoredProps = (ignoreProperties != null ? new HashSet<>(Arrays.asList(ignoreProperties)) : null);
+		CachedIntrospectionResults sourceResults = (actualEditable != source.getClass() ?
+				CachedIntrospectionResults.forClass(source.getClass()) : null);
 
 		for (PropertyDescriptor targetPd : targetPds) {
 			Method writeMethod = targetPd.getWriteMethod();
 			if (writeMethod != null && (ignoredProps == null || !ignoredProps.contains(targetPd.getName()))) {
-				PropertyDescriptor sourcePd = getPropertyDescriptor(source.getClass(), targetPd.getName());
+				PropertyDescriptor sourcePd = (sourceResults != null ?
+						sourceResults.getPropertyDescriptor(targetPd.getName()) : targetPd);
 				if (sourcePd != null) {
 					Method readMethod = sourcePd.getReadMethod();
 					if (readMethod != null) {
-						ResolvableType sourceResolvableType = ResolvableType.forMethodReturnType(readMethod);
-						ResolvableType targetResolvableType = ResolvableType.forMethodParameter(writeMethod, 0);
-
-						// Ignore generic types in assignable check if either ResolvableType has unresolvable generics.
-						boolean isAssignable =
-								(sourceResolvableType.hasUnresolvableGenerics() || targetResolvableType.hasUnresolvableGenerics() ?
-										ClassUtils.isAssignable(writeMethod.getParameterTypes()[0], readMethod.getReturnType()) :
-										targetResolvableType.isAssignableFrom(sourceResolvableType));
-
-						if (isAssignable) {
+						if (isAssignable(writeMethod, readMethod)) {
 							try {
-								if (!Modifier.isPublic(readMethod.getDeclaringClass().getModifiers())) {
-									readMethod.setAccessible(true);
-								}
+								ReflectionUtils.makeAccessible(readMethod);
 								Object value = readMethod.invoke(source);
-								if (!Modifier.isPublic(writeMethod.getDeclaringClass().getModifiers())) {
-									writeMethod.setAccessible(true);
-								}
+								ReflectionUtils.makeAccessible(writeMethod);
 								writeMethod.invoke(target, value);
 							}
 							catch (Throwable ex) {
@@ -832,6 +823,24 @@ private static void copyProperties(Object source, Object target, @Nullable Class
 		}
 	}
 
+	private static boolean isAssignable(Method writeMethod, Method readMethod) {
+		Type paramType = writeMethod.getGenericParameterTypes()[0];
+		if (paramType instanceof Class<?> clazz) {
+			return ClassUtils.isAssignable(clazz, readMethod.getReturnType());
+		}
+		else if (paramType.equals(readMethod.getGenericReturnType())) {
+			return true;
+		}
+		else {
+			ResolvableType sourceType = ResolvableType.forMethodReturnType(readMethod);
+			ResolvableType targetType = ResolvableType.forMethodParameter(writeMethod, 0);
+			// Ignore generic types in assignable check if either ResolvableType has unresolvable generics.
+			return (sourceType.hasUnresolvableGenerics() || targetType.hasUnresolvableGenerics() ?
+					ClassUtils.isAssignable(writeMethod.getParameterTypes()[0], readMethod.getReturnType()) :
+					targetType.isAssignableFrom(sourceType));
+		}
+	}
+
 
 	/**
 	 * Inner class to avoid a hard dependency on Kotlin at runtime.
@@ -896,7 +905,6 @@ public static <T> T instantiateClass(Constructor<T> ctor, Object... args)
 			}
 			return kotlinConstructor.callBy(argParameters);
 		}
-
 	}
 
 }