UPGRADE FROM 4.x to 5.0

BrowserKit

The Client::submit() method has a new $serverParameters argument.

Cache

Removed CacheItem::getPreviousTags(), use CacheItem::getMetadata() instead.

Config

Dropped support for constructing a TreeBuilder without passing root node information.
Added the getChildNodeDefinitions() method to ParentNodeDefinitionInterface.
The Processor class has been made final
Removed FileLoaderLoadException, use LoaderLoadException instead.

Console

Removed the setCrossingChar() method in favor of the setDefaultCrossingChar() method in TableStyle.
Removed the setHorizontalBorderChar() method in favor of the setDefaultCrossingChars() method in TableStyle.
Removed the getHorizontalBorderChar() method in favor of the getBorderChars() method in TableStyle.
Removed the setVerticalBorderChar() method in favor of the setVerticalBorderChars() method in TableStyle.
Removed the getVerticalBorderChar() method in favor of the getBorderChars() method in TableStyle.

The ProcessHelper::run() method takes the command as an array of arguments.

Before:

$processHelper->run($output, 'ls -l');

After:

$processHelper->run($output, array('ls', '-l'));

// alternatively, when a shell wrapper is required
$processHelper->run($output, Process::fromShellCommandline('ls -l'));

DependencyInjection

Removed the TypedReference::canBeAutoregistered() and TypedReference::getRequiringClass() methods.
Removed support for auto-discovered extension configuration class which does not implement ConfigurationInterface.

DoctrineBridge

Deprecated injecting ClassMetadataFactory in DoctrineExtractor, an instance of EntityManagerInterface should be injected instead

DomCrawler

The Crawler::children() method has a new $selector argument.

EventDispatcher

The TraceableEventDispatcherInterface has been removed.

Finder

The Finder::sortByName() method has a new $useNaturalSort argument.

Form

The getExtendedType() method was removed from the FormTypeExtensionInterface. It is replaced by the the static getExtendedTypes() method which must return an iterable of extended types.

Before:

class FooTypeExtension extends AbstractTypeExtension
{
    public function getExtendedType()
    {
        return FormType::class;
    }

    // ...
}

After:

class FooTypeExtension extends AbstractTypeExtension
{
    public static function getExtendedTypes(): iterable
    {
        return array(FormType::class);
    }

    // ...
}

The scale option was removed from the IntegerType.
The $scale argument of the IntegerToLocalizedStringTransformer was removed.

Calling FormRenderer::searchAndRenderBlock for fields which were already rendered throws an exception instead of returning empty strings:

Before:

{% for field in fieldsWithPotentialDuplicates %}
   {{ form_widget(field) }}
{% endfor %}

After:

{% for field in fieldsWithPotentialDuplicates if not field.rendered %}
   {{ form_widget(field) }}
{% endfor %}

The regions option was removed from the TimezoneType.

FrameworkBundle

Removed support for bundle:controller:action and service:action syntaxes to reference controllers. Use serviceOrFqcn::method instead where serviceOrFqcn is either the service ID when using controllers as services or the FQCN of the controller.

Before:

bundle_controller:
    path: /
    defaults:
        _controller: FrameworkBundle:Redirect:redirect

service_controller:
    path: /
    defaults:
        _controller: app.my_controller:myAction

After:

bundle_controller:
    path: /
    defaults:
        _controller: Symfony\Bundle\FrameworkBundle\Controller\RedirectController::redirectAction

service_controller:
    path: /
    defaults:
        _controller: app.my_controller::myAction

Removed Symfony\Bundle\FrameworkBundle\Controller\ControllerNameParser.
Warming up a router in RouterCacheWarmer that does not implement the WarmableInterface is not supported anymore.
The RequestDataCollector class has been removed. Use the Symfony\Component\HttpKernel\DataCollector\RequestDataCollector class instead.
Removed Symfony\Bundle\FrameworkBundle\Controller\Controller. Use Symfony\Bundle\FrameworkBundle\Controller\AbstractController instead.
Added support for the SameSite attribute for session cookies. It is highly recommended to set this setting (framework.session.cookie_samesite) to lax for increased security against CSRF attacks.
The ContainerAwareCommand class has been removed, use Symfony\Component\Console\Command\Command with dependency injection instead.
The --env console option and its "-e" shortcut have been removed, set the "APP_ENV" environment variable instead.
The --no-debug console option has been removed, set the "APP_DEBUG" environment variable to "0" instead.
The Templating\Helper\TranslatorHelper::transChoice() method has been removed, use the trans() one instead with a %count% parameter.
Removed support for legacy translations directories src/Resources/translations/ and src/Resources/<BundleName>/translations/, use translations/ instead.
Support for the legacy directory structure in translation:update and debug:translation commands has been removed.

HttpFoundation

The $size argument of the UploadedFile constructor has been removed.
The getClientSize() method of the UploadedFile class has been removed.
The getSession() method of the Request class throws an exception when session is null.
The default value of the "$secure" and "$samesite" arguments of Cookie's constructor changed respectively from "false" to "null" and from "null" to "lax".

HttpKernel

The Kernel::getRootDir() and the kernel.root_dir parameter have been removed
The KernelInterface::getName() and the kernel.name parameter have been removed
Removed the first and second constructor argument of ConfigDataCollector
Removed ConfigDataCollector::getApplicationName()
Removed ConfigDataCollector::getApplicationVersion()

Monolog

The methods DebugProcessor::getLogs(), DebugProcessor::countErrors(), Logger::getLogs() and Logger::countErrors() have a new $request argument.

Process

Removed the Process::setCommandline() and the PhpProcess::setPhpBinary() methods.

Commands must be defined as arrays when creating a Process instance.

Before:

$process = new Process('ls -l');

After:

$process = new Process(array('ls', '-l'));

// alternatively, when a shell wrapper is required
$process = Process::fromShellCommandline('ls -l');

Security

The ContextListener::setLogoutOnUserChange() method has been removed.
The Symfony\Component\Security\Core\User\AdvancedUserInterface has been removed.
The ExpressionVoter::addExpressionLanguageProvider() method has been removed.
The FirewallMapInterface::getListeners() method must return an array of 3 elements, the 3rd one must be either a LogoutListener instance or null.
The AuthenticationTrustResolver constructor arguments have been removed.
A user object that is not an instance of UserInterface cannot be accessed from Security::getUser() anymore and returns null instead.
SimpleAuthenticatorInterface, SimpleFormAuthenticatorInterface, SimplePreAuthenticatorInterface, SimpleAuthenticationProvider, SimpleAuthenticationHandler, SimpleFormAuthenticationListener and SimplePreAuthenticationListener have been removed. Use Guard instead.

SecurityBundle

The logout_on_user_change firewall option has been removed.
The switch_user.stateless firewall option has been removed.
The SecurityUserValueResolver class has been removed.
Passing a FirewallConfig instance as 3rd argument to the FirewallContext constructor now throws a \TypeError, pass a LogoutListener instance instead.
The security.authentication.trust_resolver.anonymous_class parameter has been removed.
The security.authentication.trust_resolver.rememberme_class parameter has been removed.
The simple_form and simple_preauth authentication listeners have been removed, use Guard instead.
The SimpleFormFactory and SimplePreAuthenticationFactory classes have been removed, use Guard instead.

Serializer

The AbstractNormalizer::handleCircularReference() method has two new $format and $context arguments.

Translation

The FileDumper::setBackup() method has been removed.
The TranslationWriter::disableBackup() method has been removed.
The TranslatorInterface has been removed in favor of Symfony\Contracts\Translation\TranslatorInterface
The MessageSelector, Interval and PluralizationRules classes have been removed, use IdentityTranslator instead
The Translator::getFallbackLocales() and TranslationDataCollector::getFallbackLocales() method are now internal
The Translator::transChoice() method has been removed in favor of using Translator::trans() with "%count%" as the parameter driving plurals

TwigBundle

The default value (false) of the twig.strict_variables configuration option has been changed to %kernel.debug%.
The transchoice tag and filter have been removed, use the trans ones instead with a %count% parameter.
Removed support for legacy templates directories src/Resources/views/ and src/Resources/<BundleName>/views/, use templates/ and templates/bundles/<BundleName>/ instead.

Validator

The checkMX and checkHost options of the Email constraint were removed
The Email::__construct() 'strict' property has been removed. Use 'mode'=>"strict" instead.
Calling EmailValidator::__construct() method with a boolean parameter has been removed, use EmailValidator("strict") instead.
Removed the checkDNS and dnsMessage options from the Url constraint.
The component is now decoupled from symfony/translation and uses Symfony\Contracts\Translation\TranslatorInterface instead
The ValidatorBuilderInterface has been removed and ValidatorBuilder is now final
Removed support for validating instances of \DateTimeInterface in DateTimeValidator, DateValidator and TimeValidator. Use Type instead or remove the constraint if the underlying model is type hinted to \DateTimeInterface already.
The symfony/intl component is now required for using the Bic, Country, Currency, Language and Locale constraints
The egulias/email-validator component is now required for using the Email constraint
The symfony/expression-language component is now required for using the Expression constraint

Workflow

The DefinitionBuilder::reset() method has been removed, use the clear() one instead.
add method has been removed use addWorkflow method in Workflow\Registry instead.
SupportStrategyInterface has been removed, use WorkflowSupportStrategyInterface instead.
ClassInstanceSupportStrategy has been removed, use InstanceOfSupportStrategy instead.

WebServerBundle

Omitting the $environment argument of the ServerRunCommand and ServerStartCommand constructors now throws a \TypeError.

Uh oh!