Suppress NotWritablePropertyException in case of ignoreUnknown=true

Closes gh-25986

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -431,9 +431,12 @@ public abstract class AbstractNestablePropertyAccessor extends AbstractPropertyA
 				}
 				return;
 			}
-			else {
-				throw createNotWritablePropertyException(tokens.canonicalName);
+			if (this.suppressNotWritablePropertyException) {
+				// Optimization for common ignoreUnknown=true scenario since the
+				// exception would be caught and swallowed higher up anyway...
+				return;
 			}
+			throw createNotWritablePropertyException(tokens.canonicalName);
 		}
 
 		Object oldValue = null;
@@ -815,7 +818,6 @@ public abstract class AbstractNestablePropertyAccessor extends AbstractPropertyA
 	 * @param propertyPath property path, which may be nested
 	 * @return a property accessor for the target bean
 	 */
-	@SuppressWarnings("unchecked")  // avoid nested generic
 	protected AbstractNestablePropertyAccessor getPropertyAccessorForPropertyPath(String propertyPath) {
 		int pos = PropertyAccessorUtils.getFirstNestedPropertySeparatorIndex(propertyPath);
 		// Handle nested properties recursively.

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -38,6 +38,8 @@ public abstract class AbstractPropertyAccessor extends TypeConverterSupport impl
 
 	private boolean autoGrowNestedPaths = false;
 
+	boolean suppressNotWritablePropertyException = false;
+
 
 	@Override
 	public void setExtractOldValueForEditor(boolean extractOldValueForEditor) {
@@ -87,30 +89,41 @@ public abstract class AbstractPropertyAccessor extends TypeConverterSupport impl
 		List<PropertyAccessException> propertyAccessExceptions = null;
 		List<PropertyValue> propertyValues = (pvs instanceof MutablePropertyValues ?
 				((MutablePropertyValues) pvs).getPropertyValueList() : Arrays.asList(pvs.getPropertyValues()));
-		for (PropertyValue pv : propertyValues) {
-			try {
-				// This method may throw any BeansException, which won't be caught
+
+		if (ignoreUnknown) {
+			this.suppressNotWritablePropertyException = true;
+		}
+		try {
+			for (PropertyValue pv : propertyValues) {
+				// setPropertyValue may throw any BeansException, which won't be caught
 				// here, if there is a critical failure such as no matching field.
 				// We can attempt to deal only with less serious exceptions.
-				setPropertyValue(pv);
-			}
-			catch (NotWritablePropertyException ex) {
-				if (!ignoreUnknown) {
-					throw ex;
+				try {
+					setPropertyValue(pv);
 				}
-				// Otherwise, just ignore it and continue...
-			}
-			catch (NullValueInNestedPathException ex) {
-				if (!ignoreInvalid) {
-					throw ex;
+				catch (NotWritablePropertyException ex) {
+					if (!ignoreUnknown) {
+						throw ex;
+					}
+					// Otherwise, just ignore it and continue...
 				}
-				// Otherwise, just ignore it and continue...
-			}
-			catch (PropertyAccessException ex) {
-				if (propertyAccessExceptions == null) {
-					propertyAccessExceptions = new LinkedList<PropertyAccessException>();
+				catch (NullValueInNestedPathException ex) {
+					if (!ignoreInvalid) {
+						throw ex;
+					}
+					// Otherwise, just ignore it and continue...
 				}
-				propertyAccessExceptions.add(ex);
+				catch (PropertyAccessException ex) {
+					if (propertyAccessExceptions == null) {
+						propertyAccessExceptions = new LinkedList<PropertyAccessException>();
+					}
+					propertyAccessExceptions.add(ex);
+				}
+			}
+		}
+		finally {
+			if (ignoreUnknown) {
+				this.suppressNotWritablePropertyException = false;
 			}
 		}