[Form] update 'entry_options' and 'prototype_options' in CollectionType

Author: HeahDude

reference/forms/types/collection.rst

@@ -21,6 +21,7 @@ photos).
 |             | - `entry_type`_                                                             |
 |             | - `prototype`_                                                              |
 |             | - `prototype_name`_                                                         |
+|             | - `prototype_options`_                                                      |
 +-------------+-----------------------------------------------------------------------------+
 | Inherited   | - `by_reference`_                                                           |
 | options     | - `empty_data`_                                                             |
@@ -280,7 +281,11 @@ the empty values will be kept.
 entry_options
 ~~~~~~~~~~~~~
 
-**type**: ``array`` **default**: ``array()``
+**type**: ``array`` or ``callable`` **default**: ``array()``
+
+.. versionadded:: 3.1
+
+    Since version 3.1, ``entry_options`` can be set dynamically by a callable.
 
 This is the array that's passed to the form type specified in the `entry_type`_
 option. For example, if you used the :doc:`ChoiceType </reference/forms/types/choice>`
@@ -304,6 +309,44 @@ type::
         ),
     ));
 
+The above example output each field of the collection with the same choices.
+When defined as a callable, each entry of the collection is passed to it as
+only argument and it must return a corresponding array of options::
+
+    use Symfony\Component\Form\Extension\Core\Type\CollectionType;
+    use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
+    // ...
+
+    $builder->add('favorite_places', CollectionType::class, array(
+        'entry_type' => ChoiceType::class,
+        'entry_options' => function ($choice) {
+            $options = array();
+
+            if ($choice instanceof \AppBundle\Entity\City) {
+                $options = array(
+                    'choices'  => $choice->getFamousPlaces(),
+                    'choice_value' => 'id',
+                    'choice_label' => 'localName',
+                    'choice_attr' => function ($place) {
+                        $url = '/places/'.(null === $place ? '' : $place->getSlug();
+
+                        return array(
+                            'class' => 'place_option',
+                            'attr' => array('data-url' => $url),
+                        );
+                    },
+                );
+            }
+
+            return $options;
+        },
+        'data' => $visitedCities,
+    ));
+
+Many form type have useful options that can be handy to set dynamically for
+each entries. A :class:`Symfony\Component\Form\Extension\Core\Type\HiddenType` collection would be able
+to hold specific data html attributes for each entry.
+
 entry_type
 ~~~~~~~~~~
 
@@ -363,6 +406,25 @@ If you have several collections in your form, or worse, nested collections
 you may want to change the placeholder so that unrelated placeholders are
 not replaced with the same value.
 
+prototype_options
+~~~~~~~~~~~~~~~~~
+
+**type**: ``array`` **default**: ``entry_options`` value
+
+.. versionadded:: 3.1
+
+    The ``prototype_options`` option was added in Symfony 3.1.
+
+You can pass any options that will override the corresponding default set in
+``entry_options`` option. Can be useful to pass custom css classes and data
+html attributes with the ``attr`` option to your prototype.
+
+.. note::
+
+    Since version 3.1, you should use a ``data`` key in ``prototype_options``
+    to define a default data for each new prototype instead of the deprecated
+    ``prototype_data`` option.
+
 Inherited Options
 -----------------