UPGRADE-2.6.md

UPGRADE FROM 2.5 to 2.6

Form

• The "empty_value" option in the types "choice", "date", "datetime" and "time" was deprecated and replaced by a new option "placeholder". You should use the option "placeholder" together with the view variables "placeholder" and "placeholder_in_choices" now.

  The option "empty_value" and the view variables "empty_value" and "empty_value_in_choices" will be removed in Symfony 3.0.

  Before:

  $form->add('category', 'choice', array(
      'choices' => array('politics', 'media'),
      'empty_value' => 'Select a category...',
  ));

  After:

  $form->add('category', 'choice', array(
      'choices' => array('politics', 'media'),
      'placeholder' => 'Select a category...',
  ));

  Before:

  {{ form.vars.empty_value }}
  
  {% if form.vars.empty_value_in_choices %}
      ...
  {% endif %}

  After:

  {{ form.vars.placeholder }}
  
  {% if form.vars.placeholder_in_choices %}
      ...
  {% endif %}

Validator

• The internal method setConstraint() was added to Symfony\Component\Validator\Context\ExecutionContextInterface. With this method, the context is informed about the constraint that is currently being validated.

  If you implement this interface, make sure to add the method to your implementation. The easiest solution is to just implement an empty method:

  public function setConstraint(Constraint $constraint)
  {
  }

• Prior to 2.6 Symfony\Component\Validator\Constraints\ExpressionValidator would not execute the Expression if it was attached to a property on an object and that property was set to null or an empty string.

  To emulate the old behaviour change your expression to something like this:

  value == null or (YOUR_EXPRESSION)

Security

• The SecurityContextInterface is marked as deprecated in favor of the Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface and Symfony\Component\Security\Core\Authentication\Token\Storage\TokenStorageInterface.

  isGranted  => AuthorizationCheckerInterface
  getToken   => TokenStorageInterface
  setToken   => TokenStorageInterface

  The Implementations have moved too, The SecurityContext is marked as deprecated and has been split to use the AuthorizationCheckerInterface and TokenStorage. This change is 100% Backwards Compatible as the SecurityContext delegates the methods.

• The service security.context is deprecated along with the above change. Recommended to use instead:

  @security.authorization_checker => isGranted()
  @security.token_storage         => getToken()
  @security.token_storage         => setToken()

HttpFoundation

• The PdoSessionHandler to store sessions in a database changed significantly.
  • By default, it now implements session locking to prevent loss of data by concurrent access to the same session.
    • It does so using a transaction between opening and closing a session. For this reason, it's not recommended to use the same database connection that you also use for your application logic. Otherwise you have to make sure to access your database after the session is closed and committed. Instead of passing an existing connection to the handler, you can now also pass a DSN string which will be used to lazy-connect when a session is started.
    • Since accessing a session now blocks when the same session is still open, it is best practice to save the session as soon as you don't need to write to it anymore. For example, read-only AJAX request to a session can save the session immediately after opening it to increase concurrency.
    • As alternative to transactional locking you can also use advisory locks which do not require a transaction. Additionally, you can also revert back to no locking in case you have custom logic to deal with race conditions like an optimistic concurrency control approach. The locking strategy can be chosen by passing the corresponding constant as lock_mode option, e.g. new PdoSessionHandler($pdoOrDsn, array('lock_mode' => PdoSessionHandler::LOCK_NONE)). For more information please read the class documentation.
  • The expected schema of the table changed.
    • Session data is binary text that can contain null bytes and thus should also be saved as-is in a binary column like BLOB. For this reason, the handler does not base64_encode the data anymore.
    • A new column to store the lifetime of a session is required. This allows to have different lifetimes per session configured via session.gc_maxlifetime ini setting.
    • You would need to migrate the table manually if you want to keep session information of your users.
    • You could use PdoSessionHandler::createTable to initialize a correctly defined table depending on the used database vendor.