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);
   ```

 * Registering type extensions as a service with an alias which does not
   match the type returned by `getExtendedType` is now forbidden. Fix your
   implementation to define the right type.

 * The alias option of the `form.type_extension` tag is deprecated in favor of
   the `extended_type`/`extended-type` option.

   Before:
   ```xml
   <service id="app.type_extension" class="Vendor\Form\Extension\MyTypeExtension">
       <tag name="form.type_extension" alias="text" />
   </service>
   ```

   After:
   ```xml
   <service id="app.type_extension" class="Vendor\Form\Extension\MyTypeExtension">
       <tag name="form.type_extension" extended-type="Symfony\Component\Form\Extension\Core\Type\TextType" />
   </service>
   ```

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>
   ```

WebProfiler
-----------

 * The `profiler:import` and `profiler:export` commands have been deprecated and
   will be removed in 3.0.

 * 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 %}
   ```

 * All the profiler storages different than `FileProfilerStorage` have been
   deprecated. The deprecated classes are:

    - `Symfony\Component\HttpKernel\Profiler\BaseMemcacheProfilerStorage`
    - `Symfony\Component\HttpKernel\Profiler\MemcachedProfilerStorage`
    - `Symfony\Component\HttpKernel\Profiler\MemcacheProfilerStorage`
    - `Symfony\Component\HttpKernel\Profiler\MongoDbProfilerStorage`
    - `Symfony\Component\HttpKernel\Profiler\MysqlProfilerStorage`
    - `Symfony\Component\HttpKernel\Profiler\PdoProfilerStorage`
    - `Symfony\Component\HttpKernel\Profiler\RedisProfilerStorage`
    - `Symfony\Component\HttpKernel\Profiler\SqliteProfilerStorage`

   The alternative solution is to use the `FileProfilerStorage` or create your
   own storage implementing the `ProfileStorageInterface`.

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
   ```

Security
--------

 * The AbstractToken::isGranted() method was deprecated. Instead,
   override the voteOnAttribute() method. This method has one small
   difference: it's passed the TokenInterface instead of the user:

   Before:

   ```php
   class MyCustomVoter extends AbstractVoter
   {
       // ...

       protected function isGranted($attribute, $object, $user = null)
       {
           // ...
       }
   }
   ```

   After:

   ```php
   class MyCustomVoter extends AbstractVoter
   {
       // ...

       protected function voteOnAttribute($attribute, $object, TokenInterface $token)
       {
           $user = $token->getUser();
           // ...
       }
   }
   ```

Config
------

 * The `\Symfony\Component\Config\Resource\ResourceInterface::isFresh()` method has been
   deprecated and will be removed in Symfony 3.0 because it assumes that resource
   implementations are able to check themselves for freshness.

   If you have custom resources that implement this method, change them to implement the
   `\Symfony\Component\Config\Resource\SelfCheckingResourceInterface` sub-interface instead
   of `\Symfony\Component\Config\Resource\ResourceInterface`.

   Before:

   ```php
   use Symfony\Component\Config\Resource\ResourceInterface;

   class MyCustomResource implements ResourceInterface { ... }
   ```

   After:

   ```php
   use Symfony\Component\Config\Resource\SelfCheckingResourceInterface;

   class MyCustomResource implements SelfCheckingResourceInterface { ... }
   ```

   Additionally, if you have implemented cache validation strategies *using* `isFresh()`
   yourself, you should have a look at the new cache validation system based on
   `ResourceChecker`s.