46867 - Helpful property path accessor exceptions

Adds more helpful exceptions when properties cannot be accessed/set
using forms.
Closes symfony/symfony#46867.

Extension/Core/DataAccessor/PropertyPathAccessor.php

@@ -15,7 +15,9 @@
 use Symfony\Component\Form\Exception\AccessException;
 use Symfony\Component\Form\FormInterface;
 use Symfony\Component\PropertyAccess\Exception\AccessException as PropertyAccessException;
+use Symfony\Component\PropertyAccess\Exception\NoSuchPropertyException;
 use Symfony\Component\PropertyAccess\Exception\NoSuchIndexException;
+use Symfony\Component\PropertyAccess\Exception\NoSuchPropertyException;
 use Symfony\Component\PropertyAccess\Exception\UninitializedPropertyException;
 use Symfony\Component\PropertyAccess\PropertyAccess;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
@@ -66,7 +68,13 @@ public function setValue(object|array &$data, mixed $value, FormInterface $form)
         // If the data is identical to the value in $data, we are
         // dealing with a reference
         if (!\is_object($data) || !$form->getConfig()->getByReference() || $value !== $this->getPropertyValue($data, $propertyPath)) {
-            $this->propertyAccessor->setValue($data, $propertyPath, $value);
+            try {
+                $this->propertyAccessor->setValue($data, $propertyPath, $value);
+            } catch (NoSuchPropertyException $e) {
+                throw new NoSuchPropertyException(
+                    $e->getMessage() . ' Make the property public, add a setter, or set the "mapped" field option in the form type to be false.'
+                );
+            }
         }
     }
 
@@ -91,13 +99,14 @@ private function getPropertyValue(object|array $data, PropertyPathInterface $pro
         try {
             return $this->propertyAccessor->getValue($data, $propertyPath);
         } catch (PropertyAccessException $e) {
-            if (\is_array($data) && $e instanceof NoSuchIndexException) {
-                return null;
+            if ($e instanceof NoSuchPropertyException) {
+                throw new NoSuchPropertyException(
+                    $e->getMessage() . ' Make the property public, add a getter, or set the "mapped" field option in the form type to be false.'
+                );
             }
-
             if (!$e instanceof UninitializedPropertyException
                 // For versions without UninitializedPropertyException check the exception message
-                && (class_exists(UninitializedPropertyException::class) || !str_contains($e->getMessage(), 'You should initialize it'))
+                && (class_exists(UninitializedPropertyException::class) || false === strpos($e->getMessage(), 'You should initialize it'))
             ) {
                 throw $e;
             }