[Form] Added option "data_constructor" to Form. When a Form is initialized with NULL, an object is automatically created using this constructor. If no constructor is given but the option "data_class" is set, an object of that class is created with the default constructor instead.

src/Symfony/Component/Form/Form.php

@@ -58,6 +58,12 @@ class Form extends Field implements \IteratorAggregate, FormInterface
      */
     protected $dataClass;
 
+    /**
+     * Stores the constructor closure for creating new domain object instances
+     * @var \Closure
+     */
+    protected $dataConstructor;
+
     /**
      * The context used when creating the form
      * @var FormContext
@@ -86,6 +92,7 @@ class Form extends Field implements \IteratorAggregate, FormInterface
     public function __construct($name = null, array $options = array())
     {
         $this->addOption('data_class');
+        $this->addOption('data_constructor');
         $this->addOption('csrf_field_name', '_token');
         $this->addOption('csrf_provider');
         $this->addOption('field_factory');
@@ -103,6 +110,14 @@ class Form extends Field implements \IteratorAggregate, FormInterface
             $this->dataClass = $options['data_class'];
         }
 
+        if (isset($options['data_constructor'])) {
+            $this->dataConstructor = $options['data_constructor'];
+        } else {
+            $this->dataConstructor = function ($class) {
+                return new $class();
+            };
+        }
+
         parent::__construct($name, $options);
 
         // Enable CSRF protection
@@ -341,6 +356,11 @@ class Form extends Field implements \IteratorAggregate, FormInterface
      */
     public function setData($data)
     {
+        if (empty($data) && $this->dataClass) {
+            $constructor = $this->dataConstructor;
+            $data = $constructor($this->dataClass);
+        }
+
         parent::setData($data);
 
         // get transformed data and pass its values to child fields

tests/Symfony/Tests/Component/Form/FormTest.php

@@ -991,6 +991,41 @@ class FormTest extends \PHPUnit_Framework_TestCase
         $form->setData(new Author());
     }
 
+    public function testSetDataToNull()
+    {
+        $form = new Form('author');
+        $form->setData(null);
+
+        $this->assertNull($form->getData());
+    }
+
+    public function testSetDataToNullCreatesObjectIfClassAvailable()
+    {
+        $form = new Form('author', array(
+            'data_class' => 'Symfony\Tests\Component\Form\Fixtures\Author',
+        ));
+        $form->setData(null);
+
+        $this->assertEquals(new Author(), $form->getData());
+    }
+
+    public function testSetDataToNullUsesDataConstructorOption()
+    {
+        $test = $this;
+        $author = new Author();
+        $form = new Form('author', array(
+            'data_class' => 'Symfony\Tests\Component\Form\Fixtures\Author',
+            'data_constructor' => function ($class) use ($test, $author) {
+                $test->assertEquals('Symfony\Tests\Component\Form\Fixtures\Author', $class);
+
+                return $author;
+            }
+        ));
+        $form->setData(null);
+
+        $this->assertSame($author, $form->getData());
+    }
+
     public function testSubmitUpdatesTransformedDataFromAllFields()
     {
         $originalAuthor = new Author();