[Form] Added delete_empty option to allow proper emptyData handling of collections

src/Symfony/Component/Form/Extension/Core/EventListener/ResizeFormListener.php

@@ -45,12 +45,18 @@ class ResizeFormListener implements EventSubscriberInterface
      */
     protected $allowDelete;
 
-    public function __construct($type, array $options = array(), $allowAdd = false, $allowDelete = false)
+    /**
+     * @var bool
+     */
+    private $deleteEmpty;
+
+    public function __construct($type, array $options = array(), $allowAdd = false, $allowDelete = false, $deleteEmpty = false)
     {
         $this->type = $type;
         $this->allowAdd = $allowAdd;
         $this->allowDelete = $allowDelete;
         $this->options = $options;
+        $this->deleteEmpty = $deleteEmpty;
     }
 
     public static function getSubscribedEvents()
@@ -126,8 +132,13 @@ public function preSubmit(FormEvent $event)
     public function onSubmit(FormEvent $event)
     {
         $form = $event->getForm();
+        $previousData = $event->getForm()->getData();
         $data = $event->getData();
 
+        // At this point, $data is an array or an array-like object that already contains the
+        // new entries, which were added by the data mapper. The data mapper ignores existing
+        // entries, so we need to manually unset removed entries in the collection.
+
         if (null === $data) {
             $data = array();
         }
@@ -136,10 +147,23 @@ public function onSubmit(FormEvent $event)
             throw new UnexpectedTypeException($data, 'array or (\Traversable and \ArrayAccess)');
         }
 
+        if ($this->deleteEmpty) {
+            foreach ($form as $name => $child) {
+                $isNew = !isset($previousData[$name]);
+
+                // $isNew can only be true if allowAdd is true, so we don't
+                // need to check allowAdd again
+                if ($child->isEmpty() && ($isNew || $this->allowDelete)) {
+                    unset($data[$name]);
+                    $form->remove($name);
+                }
+            }
+        }
+
         // The data mapper only adds, but does not remove items, so do this
         // here
         if ($this->allowDelete) {
-            foreach ($data as $name => $child) {
+            foreach ($data as $name => $childData) {
                 if (!$form->has($name)) {
                     unset($data[$name]);
                 }

src/Symfony/Component/Form/Extension/Core/Type/CollectionType.php

@@ -37,7 +37,8 @@ public function buildForm(FormBuilderInterface $builder, array $options)
             $options['type'],
             $options['options'],
             $options['allow_add'],
-            $options['allow_delete']
+            $options['allow_delete'],
+            $options['delete_empty']
         );
 
         $builder->addEventSubscriber($resizeListener);
@@ -86,6 +87,7 @@ public function setDefaultOptions(OptionsResolverInterface $resolver)
             'prototype_name' => '__name__',
             'type'           => 'text',
             'options'        => array(),
+            'delete_empty'   => false,
         ));
 
         $resolver->setNormalizers(array(

src/Symfony/Component/Form/Form.php

@@ -899,7 +899,9 @@ public function remove($name)
         }
 
         if (isset($this->children[$name])) {
-            $this->children[$name]->setParent(null);
+            if (!$this->children[$name]->isSubmitted()) {
+                $this->children[$name]->setParent(null);
+            }
 
             unset($this->children[$name]);
         }

src/Symfony/Component/Form/Tests/Extension/Core/Type/CollectionTypeTest.php

@@ -12,6 +12,8 @@
 namespace Symfony\Component\Form\Tests\Extension\Core\Type;
 
 use Symfony\Component\Form\Form;
+use Symfony\Component\Form\Tests\Fixtures\Author;
+use Symfony\Component\Form\Tests\Fixtures\AuthorType;
 
 class CollectionTypeTest extends \Symfony\Component\Form\Test\TypeTestCase
 {
@@ -88,6 +90,79 @@ public function testResizedDownIfSubmittedWithMissingDataAndAllowDelete()
         $this->assertEquals(array('foo@foo.com'), $form->getData());
     }
 
+
+    public function testResizedDownIfSubmittedWithEmptyDataAndDeleteEmpty()
+    {
+        $form = $this->factory->create('collection', null, array(
+            'type' => 'text',
+            'allow_delete' => true,
+            'delete_empty' => true,
+        ));
+
+        $form->setData(array('foo@foo.com', 'bar@bar.com'));
+        $form->submit(array('foo@foo.com', ''));
+
+        $this->assertTrue($form->has('0'));
+        $this->assertFalse($form->has('1'));
+        $this->assertEquals('foo@foo.com', $form[0]->getData());
+        $this->assertEquals(array('foo@foo.com'), $form->getData());
+    }
+
+    public function testDontAddEmptyDataIfDeleteEmpty()
+    {
+        $form = $this->factory->create('collection', null, array(
+            'type' => 'text',
+            'allow_add' => true,
+            'delete_empty' => true,
+        ));
+
+        $form->setData(array('foo@foo.com'));
+        $form->submit(array('foo@foo.com', ''));
+
+        $this->assertTrue($form->has('0'));
+        $this->assertFalse($form->has('1'));
+        $this->assertEquals('foo@foo.com', $form[0]->getData());
+        $this->assertEquals(array('foo@foo.com'), $form->getData());
+    }
+
+    public function testNoDeleteEmptyIfDeleteNotAllowed()
+    {
+        $form = $this->factory->create('collection', null, array(
+            'type' => 'text',
+            'allow_delete' => false,
+            'delete_empty' => true,
+        ));
+
+        $form->setData(array('foo@foo.com'));
+        $form->submit(array(''));
+
+        $this->assertTrue($form->has('0'));
+        $this->assertEquals('', $form[0]->getData());
+    }
+
+    public function testResizedDownIfSubmittedWithCompoundEmptyDataAndDeleteEmpty()
+    {
+        $form = $this->factory->create('collection', null, array(
+            'type' => new AuthorType(),
+            // If the field is not required, no new Author will be created if the
+            // form is completely empty
+            'options' => array('required' => false),
+            'allow_add' => true,
+            'delete_empty' => true,
+        ));
+
+        $form->setData(array(new Author('first', 'last')));
+        $form->submit(array(
+            array('firstName' => 's_first', 'lastName' => 's_last'),
+            array('firstName' => '', 'lastName' => ''),
+        ));
+
+        $this->assertTrue($form->has('0'));
+        $this->assertFalse($form->has('1'));
+        $this->assertEquals(new Author('s_first', 's_last'), $form[0]->getData());
+        $this->assertEquals(array(new Author('s_first', 's_last')), $form->getData());
+    }
+
     public function testNotResizedIfSubmittedWithExtraData()
     {
         $form = $this->factory->create('collection', null, array(

src/Symfony/Component/Form/Tests/Fixtures/Author.php

@@ -21,6 +21,12 @@ class Author
 
     private $privateProperty;
 
+    public function __construct($firstName = null, $lastName = null)
+    {
+        $this->firstName = $firstName;
+        $this->lastName = $lastName;
+    }
+
     public function setLastName($lastName)
     {
         $this->lastName = $lastName;