Correctly set auto-growing array's element

Prior to this commit, the implementation of processKeyedProperty() in
AbstractNestablePropertyAccessor resulted in a
`java.lang.IllegalArgumentException: array element type mismatch` when
the property expression had more than one property key and the last key
should cause the array to grow automatically.

For example, given a property `int[][] multiArray` and property
expression `multiArray[1][3]`, the `processKeyedProperty()` method
created a new array object and assigned it to `multiArray`; whereas,
the new array object should have be assigned to `multiArray[1]`.

This commit fixes this issue.

Closes spring-projectsgh-26600

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

@@ -305,8 +305,10 @@ private void processKeyedProperty(PropertyTokenHolder tokens, PropertyValue pv)
 					Class<?> componentType = propValue.getClass().getComponentType();
 					Object newArray = Array.newInstance(componentType, arrayIndex + 1);
 					System.arraycopy(propValue, 0, newArray, 0, length);
-					setPropertyValue(tokens.actualName, newArray);
-					propValue = getPropertyValue(tokens.actualName);
+					int lastKeyIndex = tokens.canonicalName.lastIndexOf('[');
+					String propName = tokens.canonicalName.substring(0, lastKeyIndex);
+					setPropertyValue(propName, newArray);
+					propValue = getPropertyValue(propName);
 				}
 				Array.set(propValue, arrayIndex, convertedValue);
 			}

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

@@ -99,6 +99,12 @@ public void getPropertyValueAutoGrowMultiDimensionalArray() {
 		assertThat(bean.getMultiArray()[0][0]).isInstanceOf(Bean.class);
 	}
 
+	@Test
+	public void setPropertyValueAutoGrowMultiDimensionalArray() {
+		wrapper.setPropertyValue("multiArray[2][3]", new Bean());
+		assertThat(bean.getMultiArray()[2][3]).isInstanceOf(Bean.class);
+	}
+
 	@Test
 	public void getPropertyValueAutoGrowList() {
 		assertNotNull(wrapper.getPropertyValue("list[0]"));