UPGRADE FROM 2.7 to 2.8
=======================

Form
----

 * The "cascade_validation" option was deprecated. Use the "constraints"
   option together with the `Valid` constraint instead. Contrary to
   "cascade_validation", "constraints" must be set on the respective child forms,
   not the parent form.

   Before:

   ```php
   $form = $this->createFormBuilder($article, array('cascade_validation' => true))
       ->add('author', new AuthorType())
       ->getForm();
   ```

   After:

   ```php
   use Symfony\Component\Validator\Constraints\Valid;
   
   $form = $this->createFormBuilder($article)
       ->add('author', new AuthorType(), array(
           'constraints' => new Valid(),
       ))
       ->getForm();
   ```

   Alternatively, you can set the `Valid` constraint in the model itself:

   ```php
   use Symfony\Component\Validator\Constraints as Assert;

   class Article
   {
       /**
        * @Assert\Valid
        */
       private $author;
   }
   ```
   
 * Type names were deprecated and will be removed in Symfony 3.0. Instead of
   referencing types by name, you should reference them by their
   fully-qualified class name (FQCN) instead. With PHP 5.5 or later, you can
   use the "class" constant for that:
   
   Before:
   
   ```php
   $form = $this->createFormBuilder()
       ->add('name', 'text')
       ->add('age', 'integer')
       ->getForm();
   ```
   
   After:
   
   ```php
   use Symfony\Component\Form\Extension\Core\Type\IntegerType;
   use Symfony\Component\Form\Extension\Core\Type\TextType;
   
   $form = $this->createFormBuilder()
       ->add('name', TextType::class)
       ->add('age', IntegerType::class)
       ->getForm();
   ```
   
   As a further consequence, the method `FormTypeInterface::getName()` was
   deprecated and will be removed in Symfony 3.0. You should remove this method
   from your form types.
   
   If you want to customize the block prefix of a type in Twig, you should now
   implement `FormTypeInterface::getBlockPrefix()` instead:
   
   Before:
   
   ```php
   class UserProfileType extends AbstractType
   {
       public function getName()
       {
           return 'profile';
       }
   }
   ```
   
   After:
   
   ```php
   class UserProfileType extends AbstractType
   {
       public function getBlockPrefix()
       {
           return 'profile';
       }
   }
   ```
   
   If you don't customize `getBlockPrefix()`, it defaults to the class name
   without "Type" suffix in underscore notation (here: "user_profile").
   
   If you want to create types that are compatible with Symfony 2.3 up to 2.8
   and don't trigger deprecation errors, implement *both* `getName()` and
   `getBlockPrefix()`:
   
   ```php
   class ProfileType extends AbstractType
   {
       public function getName()
       {
           return $this->getBlockPrefix();
       }
       
       public function getBlockPrefix()
       {
           return 'profile';
       }
   }
   ```
   
   If you define your form types in the Dependency Injection configuration, you
   should further remove the "alias" attribute:
   
   Before:
   
   ```xml
   <service id="my.type" class="Vendor\Type\MyType">
       <tag name="form.type" alias="mytype" />
   </service>
   ```
   
   After:
   
   ```xml
   <service id="my.type" class="Vendor\Type\MyType">
       <tag name="form.type" />
   </service>
   ```
   
   Type extension should return the fully-qualified class name of the extended
   type from `FormTypeExtensionInterface::getExtendedType()` now.
   
   Before:
   
   ```php
   class MyTypeExtension extends AbstractTypeExtension
   {
       public function getExtendedType()
       {
           return 'form';
       }
   }
   ```
   
   After:
   
   ```php
   use Symfony\Component\Form\Extension\Core\Type\FormType;
   
   class MyTypeExtension extends AbstractTypeExtension
   {
       public function getExtendedType()
       {
           return FormType::class;
       }
   }
   ```
   
   If your extension has to be compatible with Symfony 2.3-2.8, use the 
   following statement:
   
   ```php
   use Symfony\Component\Form\AbstractType;
   use Symfony\Component\Form\Extension\Core\Type\FormType;
   
   class MyTypeExtension extends AbstractTypeExtension
   {
       public function getExtendedType()
       {
           return method_exists(AbstractType::class, 'getBlockPrefix') ? FormType::class : 'form';
       }
   }
   ```
   
 * Returning type instances from `FormTypeInterface::getParent()` is deprecated
   and will not be supported anymore in Symfony 3.0. Return the fully-qualified
   class name of the parent type class instead.
   
   Before:
   
   ```php
   class MyType
   {
       public function getParent()
       {
           return new ParentType();
       }
   }
   ```
   
   After:
   
   ```php
   class MyType
   {
       public function getParent()
       {
           return ParentType::class;
       }
   }
   ```
   
 * Passing type instances to `Form::add()`, `FormBuilder::add()` and the
   `FormFactory::create*()` methods is deprecated and will not be supported
   anymore in Symfony 3.0. Pass the fully-qualified class name of the type
   instead.
   
   Before:
   
   ```php
   $form = $this->createForm(new MyType());
   ```
   
   After:
   
   ```php
   $form = $this->createForm(MyType::class);
   ```

Translator
----------

 * The `getMessages()` method of the `Symfony\Component\Translation\Translator` was deprecated and will be removed in
   Symfony 3.0. You should use the `getCatalogue()` method of the `Symfony\Component\Translation\TranslatorBagInterface`.

   Before:

   ```php
   $messages = $translator->getMessages();
   ```

   After:

   ```php
    $catalogue = $translator->getCatalogue($locale);
    $messages = $catalogue->all();

    while ($catalogue = $catalogue->getFallbackCatalogue()) {
        $messages = array_replace_recursive($catalogue->all(), $messages);
    }
   ```

DependencyInjection
-------------------

 * The concept of scopes were deprecated, the deprecated methods are:

    - `Symfony\Component\DependencyInjection\ContainerBuilder::getScopes()`
    - `Symfony\Component\DependencyInjection\ContainerBuilder::getScopeChildren()`
    - `Symfony\Component\DependencyInjection\ContainerInterface::enterScope()`
    - `Symfony\Component\DependencyInjection\ContainerInterface::leaveScope()`
    - `Symfony\Component\DependencyInjection\ContainerInterface::addScope()`
    - `Symfony\Component\DependencyInjection\ContainerInterface::hasScope()`
    - `Symfony\Component\DependencyInjection\ContainerInterface::isScopeActive()`
    - `Symfony\Component\DependencyInjection\Definition::setScope()`
    - `Symfony\Component\DependencyInjection\Definition::getScope()`
    - `Symfony\Component\DependencyInjection\Reference::isStrict()`

  Also, the `$scope` and `$strict` parameters of `Symfony\Component\DependencyInjection\ContainerInterface::set()` and `Symfony\Component\DependencyInjection\Reference` respectively were deprecated.

 * A new `shared` flag has been added to the service definition
   in replacement of the `prototype` scope.

   Before:

   ```php
   use Symfony\Component\DependencyInjection\ContainerBuilder;

   $container = new ContainerBuilder();
   $container
       ->register('foo', 'stdClass')
       ->setScope(ContainerBuilder::SCOPE_PROTOTYPE)
   ;
   ```

   ```yml
   services:
       foo:
           class: stdClass
           scope: prototype
   ```

   ```xml
   <services>
       <service id="foo" class="stdClass" scope="prototype" />
   </services>
   ```

   After:

   ```php
   use Symfony\Component\DependencyInjection\ContainerBuilder;

   $container = new ContainerBuilder();
   $container
       ->register('foo', 'stdClass')
       ->setShared(false)
   ;
   ```

   ```yml
   services:
       foo:
           class: stdClass
           shared: false
   ```

   ```xml
   <services>
       <service id="foo" class="stdClass" shared="false" />
   </services>
   ```

Web Development Toolbar
-----------------------

The web development toolbar has been completely redesigned. This update has
introduced some changes in the HTML markup of the toolbar items.

Before:

Information was wrapped with simple `<span>` elements:

```twig
{% block toolbar %}
    {% set icon %}
        <span>
            <svg ...></svg>
            <span>{{ '%.1f'|format(collector.memory / 1024 / 1024) }} MB</span>
        </span>
    {% endset %}
{% endblock %}
```

After:

Information is now semantically divided into values and labels according to
the `class` attribute of each `<span>` element:

```twig
{% block toolbar %}
    {% set icon %}
        <svg ...></svg>
        <span class="sf-toolbar-value">
            {{ '%.1f'|format(collector.memory / 1024 / 1024) }}
        </span>
        <span class="sf-toolbar-label">MB</span>
    {% endset %}
{% endblock %}
```

Most of the blocks designed for the previous toolbar will still be displayed
correctly. However, if you want to support both the old and the new toolbar,
it's better to make use of the new `profiler_markup_version` variable passed
to the toolbar templates:

```twig
{% block toolbar %}
    {% set profiler_markup_version = profiler_markup_version|default(1) %}

    {% set icon %}
        {% if profiler_markup_version == 1 %}

            {# code for the original toolbar #}

        {% else %}

            {# code for the new toolbar (Symfony 2.8+) #}

        {% endif %}
    {% endset %}
{% endblock %}
```

FrameworkBundle
---------------

 * The default value of the parameter `session`.`cookie_httponly` is now `true`.
   It prevents scripting languages, such as JavaScript to access the cookie,
   which help to reduce identity theft through XSS attacks. If your
   application needs to access the session cookie, override this parameter:

   ```yaml
   framework:
       session:
           cookie_httponly: false
   ```

Config
------

The edge case of defining just one value for nodes of type Enum is now allowed:

```php
$rootNode
    ->children()
        ->enumNode('variable')
            ->values(array('value'))
        ->end()
    ->end()
;
```

Before: `InvalidArgumentException` (variable must contain at least two
distinct elements).
After: the code will work as expected and it will restrict the values of the
`variable` option to just `value`.