symfony
diff --git a/‎src/Symfony/Component/Form/Extension/Core/DataMapper/PropertyPathMapper.php
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+21-3Lines changed: 21 additions & 3 deletions b/‎src/Symfony/Component/Form/Extension/Core/DataMapper/PropertyPathMapper.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Form/Extension/Core/DataMapper/PropertyPathMapper.php
+21-3Lines changed: 21 additions & 3 deletions
diff --git a/‎src/Symfony/Component/Form/Tests/Extension/Core/DataMapper/PropertyPathMapperTest.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Form/Tests/Extension/Core/DataMapper/PropertyPathMapperTest.php
+35-2Lines changed: 35 additions & 2 deletions b/‎src/Symfony/Component/Form/Tests/Extension/Core/DataMapper/PropertyPathMapperTest.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Form/Tests/Extension/Core/DataMapper/PropertyPathMapperTest.php
+35-2Lines changed: 35 additions & 2 deletions
diff --git a/‎src/Symfony/Component/Form/Tests/Fixtures/TypehintedPropertiesCar.php
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+18Lines changed: 18 additions & 0 deletions b/‎src/Symfony/Component/Form/Tests/Fixtures/TypehintedPropertiesCar.php
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+18Lines changed: 18 additions & 0 deletions
@@ -13,6 +13,8 @@
 
 use Symfony\Component\Form\DataMapperInterface;
 use Symfony\Component\Form\Exception\UnexpectedTypeException;
+use Symfony\Component\PropertyAccess\Exception\AccessException;
+use Symfony\Component\PropertyAccess\Exception\UninitializedPropertyException;
 use Symfony\Component\PropertyAccess\PropertyAccess;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
 
@@ -46,7 +48,7 @@ public function mapDataToForms($data, $forms)
             $config = $form->getConfig();
 
             if (!$empty && null !== $propertyPath && $config->getMapped()) {
-                $form->setData($this->propertyAccessor->getValue($data, $propertyPath));
+                $form->setData($this->getPropertyValue($data, $propertyPath));
             } else {
                 $form->setData($config->getData());
             }
@@ -76,16 +78,32 @@ public function mapFormsToData($forms, &$data)
                 $propertyValue = $form->getData();
                 // If the field is of type DateTimeInterface and the data is the same skip the update to
                 // keep the original object hash
-                if ($propertyValue instanceof \DateTimeInterface && $propertyValue == $this->propertyAccessor->getValue($data, $propertyPath)) {
+                if ($propertyValue instanceof \DateTimeInterface && $propertyValue == $this->getPropertyValue($data, $propertyPath)) {
                     continue;
                 }
 
                 // If the data is identical to the value in $data, we are
                 // dealing with a reference
-                if (!\is_object($data) || !$config->getByReference() || $propertyValue !== $this->propertyAccessor->getValue($data, $propertyPath)) {
+                if (!\is_object($data) || !$config->getByReference() || $propertyValue !== $this->getPropertyValue($data, $propertyPath)) {
                     $this->propertyAccessor->setValue($data, $propertyPath, $propertyValue);
                 }
             }
         }
     }
+
+    private function getPropertyValue($data, $propertyPath)
+    {
+        try {
+            return $this->propertyAccessor->getValue($data, $propertyPath);
+        } catch (AccessException $e) {
+            if (!$e instanceof UninitializedPropertyException
+                // For versions without UninitializedPropertyException check the exception message
+                && (class_exists(UninitializedPropertyException::class) || false === strpos($e->getMessage(), 'You should initialize it'))
+            ) {
+                throw $e;
+            }
+
+            return null;
+        }
+    }
 }
@@ -17,6 +17,7 @@
 use Symfony\Component\Form\Extension\Core\DataMapper\PropertyPathMapper;
 use Symfony\Component\Form\Form;
 use Symfony\Component\Form\FormConfigBuilder;
+use Symfony\Component\Form\Tests\Fixtures\TypehintedPropertiesCar;
 use Symfony\Component\PropertyAccess\PropertyAccess;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
 use Symfony\Component\PropertyAccess\PropertyPath;
@@ -113,6 +114,23 @@ public function testMapDataToFormsIgnoresUnmapped()
         $this->assertNull($form->getData());
     }
 
+    /**
+     * @requires PHP 7.4
+     */
+    public function testMapDataToFormsIgnoresUninitializedProperties()
+    {
+        $engineForm = new Form(new FormConfigBuilder('engine', null, $this->dispatcher));
+        $colorForm = new Form(new FormConfigBuilder('color', null, $this->dispatcher));
+
+        $car = new TypehintedPropertiesCar();
+        $car->engine = 'BMW';
+
+        $this->mapper->mapDataToForms($car, [$engineForm, $colorForm]);
+
+        $this->assertSame($car->engine, $engineForm->getData());
+        $this->assertNull($colorForm->getData());
+    }
+
     public function testMapDataToFormsSetsDefaultDataIfPassedDataIsNull()
     {
         $default = new \stdClass();
@@ -293,13 +311,28 @@ public function testMapFormsToDataIgnoresDisabled()
         $config->setPropertyPath($propertyPath);
         $config->setData($engine);
         $config->setDisabled(true);
-        $form = new Form($config);
+        $form = new SubmittedForm($config);
 
         $this->mapper->mapFormsToData([$form], $car);
 
         $this->assertSame($initialEngine, $car->engine);
     }
 
+    /**
+     * @requires PHP 7.4
+     */
+    public function testMapFormsToUninitializedProperties()
+    {
+        $car = new TypehintedPropertiesCar();
+        $config = new FormConfigBuilder('engine', null, $this->dispatcher);
+        $config->setData('BMW');
+        $form = new SubmittedForm($config);
+
+        $this->mapper->mapFormsToData([$form], $car);
+
+        $this->assertSame('BMW', $car->engine);
+    }
+
     /**
      * @dataProvider provideDate
      */
@@ -339,7 +372,7 @@ public function isSubmitted()
     }
 }
 
-class NotSynchronizedForm extends Form
+class NotSynchronizedForm extends SubmittedForm
 {
     public function isSynchronized()
     {
 
@@ -0,0 +1,18 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Form\Tests\Fixtures;
+
+class TypehintedPropertiesCar
+{
+    public ?string $engine;
+    public ?string $color;
+}