symfony · Jean-Beru · Dec 7, 2023 · Dec 26, 2023 · Dec 29, 2023 · Jan 2, 2024
diff --git a/composer.json b/composer.json
@@ -75,6 +75,7 @@
         "symfony/error-handler": "self.version",
         "symfony/event-dispatcher": "self.version",
         "symfony/expression-language": "self.version",
+        "symfony/feature-flag": "self.version",
         "symfony/filesystem": "self.version",
         "symfony/finder": "self.version",
         "symfony/form": "self.version",

diff --git a/src/Symfony/Bridge/Twig/Extension/FeatureFlagExtension.php b/src/Symfony/Bridge/Twig/Extension/FeatureFlagExtension.php
@@ -0,0 +1,26 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bridge\Twig\Extension;
+
+use Twig\Extension\AbstractExtension;
+use Twig\TwigFunction;
+
+final class FeatureFlagExtension extends AbstractExtension
+{
+    public function getFunctions(): array
+    {
+        return [
+            new TwigFunction('feature_is_enabled', [FeatureFlagRuntime::class, 'isEnabled']),
+            new TwigFunction('feature_get_value', [FeatureFlagRuntime::class, 'getValue']),
+        ];
+    }
+}
diff --git a/src/Symfony/Bridge/Twig/Extension/FeatureFlagRuntime.php b/src/Symfony/Bridge/Twig/Extension/FeatureFlagRuntime.php
@@ -0,0 +1,32 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bridge\Twig\Extension;
+
+use Symfony\Component\FeatureFlag\FeatureCheckerInterface;
+
+final class FeatureFlagRuntime
+{
+    public function __construct(
+        private readonly FeatureCheckerInterface $featureChecker,
+    ) {
+    }
+
+    public function isEnabled(string $featureName): bool
+    {
+        return $this->featureChecker->isEnabled($featureName);
+    }
+
+    public function getValue(string $featureName): mixed
+    {
+        return $this->featureChecker->getValue($featureName);
+    }
+}
diff --git a/src/Symfony/Bridge/Twig/UndefinedCallableHandler.php b/src/Symfony/Bridge/Twig/UndefinedCallableHandler.php
@@ -60,6 +60,8 @@ class UndefinedCallableHandler
         'field_choices' => 'form',
         'logout_url' => 'security-http',
         'logout_path' => 'security-http',
+        'feature_get_value' => 'feature-flag',
+        'feature_is_enabled' => 'feature-flag',
         'is_granted' => 'security-core',
         'is_granted_for_user' => 'security-core',
         'impersonation_path' => 'security-http',

diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/FeatureFlagPass.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/FeatureFlagPass.php
@@ -0,0 +1,95 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bundle\FrameworkBundle\DependencyInjection\Compiler;
+
+use Symfony\Component\DependencyInjection\ChildDefinition;
+use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\Definition;
+use Symfony\Component\DependencyInjection\Reference;
+use Symfony\Component\FeatureFlag\Debug\TraceableFeatureChecker;
+
+class FeatureFlagPass implements CompilerPassInterface
+{
+    public function process(ContainerBuilder $container): void
+    {
+        if (!$container->hasDefinition('feature_flag.feature_checker')) {
+            return;
+        }
+
+        $features = [];
+        foreach ($container->findTaggedServiceIds('feature_flag.feature') as $serviceId => $tags) {
+            $className = $this->getServiceClass($container, $serviceId);
+            $r = $container->getReflectionClass($className);
+
+            if (null === $r) {
+                throw new \RuntimeException(\sprintf('Invalid service "%s": class "%s" does not exist.', $serviceId, $className));
+            }
+
+            foreach ($tags as $tag) {
+                $featureName = ($tag['feature'] ?? '') ?: $className;
+                if (\array_key_exists($featureName, $features)) {
+                    throw new \RuntimeException(\sprintf('Feature "%s" already defined in the "feature_flag.provider.in_memory" provider.', $featureName));
+                }
+
+                $method = $tag['method'] ?? '__invoke';
+                if (!$r->hasMethod($method)) {
+                    throw new \RuntimeException(\sprintf('Invalid feature method "%s": method "%s::%s()" does not exist.', $serviceId, $r->getName(), $method));
+                }
+                if (!$r->getMethod($method)->isPublic()) {
+                    throw new \RuntimeException(\sprintf('Invalid feature method "%s": method "%s::%s()" must be public.', $serviceId, $r->getName(), $method));
+                }
+
+                $features[$featureName] = $container->setDefinition(
+                    '.feature_flag.feature',
+                    (new Definition(\Closure::class))
+                        ->setLazy(true)
+                        ->setFactory([\Closure::class, 'fromCallable'])
+                        ->setArguments([[new Reference($serviceId), $method]]),
+                );
+            }
+        }
+
+        $container->getDefinition('feature_flag.provider.in_memory')
+            ->setArgument('$features', $features)
+        ;
+
+        if (!$container->has('feature_flag.data_collector')) {
+            return;
+        }
+
+        foreach ($container->findTaggedServiceIds('feature_flag.feature_checker') as $serviceId => $tags) {
+            $container->register('debug.'.$serviceId, TraceableFeatureChecker::class)
+                ->setDecoratedService($serviceId)
+                ->setArguments([
+                    '$decorated' => new Reference('.inner'),
+                    '$dataCollector' => new Reference('feature_flag.data_collector'),
+                ])
+            ;
+        }
+    }
+
+    private function getServiceClass(ContainerBuilder $container, string $serviceId): ?string
+    {
+        while (true) {
+            $definition = $container->findDefinition($serviceId);
+
+            if (!$definition->getClass() && $definition instanceof ChildDefinition) {
+                $serviceId = $definition->getParent();
+
+                continue;
+            }
+
+            return $definition->getClass();
+        }
+    }
+}
diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/UnusedTagsPass.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/UnusedTagsPass.php
@@ -48,6 +48,9 @@ class UnusedTagsPass implements CompilerPassInterface
         'controller.targeted_value_resolver',
         'data_collector',
         'event_dispatcher.dispatcher',
+        'feature_flag.feature',
+        'feature_flag.feature_checker',
+        'feature_flag.provider',
         'form.type',
         'form.type_extension',
         'form.type_guesser',

diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
@@ -26,6 +26,7 @@
 use Symfony\Component\Config\Definition\Exception\InvalidConfigurationException;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Exception\LogicException;
+use Symfony\Component\FeatureFlag\FeatureCheckerInterface;
 use Symfony\Component\Form\Form;
 use Symfony\Component\HtmlSanitizer\HtmlSanitizerInterface;
 use Symfony\Component\HttpClient\HttpClient;
@@ -184,6 +185,7 @@ public function getConfigTreeBuilder(): TreeBuilder
         $this->addWebhookSection($rootNode, $enableIfStandalone);
         $this->addRemoteEventSection($rootNode, $enableIfStandalone);
         $this->addJsonStreamerSection($rootNode, $enableIfStandalone);
+        $this->addFeatureFlagSection($rootNode, $enableIfStandalone);
 
         return $treeBuilder;
     }
@@ -2742,4 +2744,16 @@ private function addJsonStreamerSection(ArrayNodeDefinition $rootNode, callable
             ->end()
         ;
     }
+
+    private function addFeatureFlagSection(ArrayNodeDefinition $rootNode, callable $enableIfStandalone): void
+    {
+        $rootNode
+            ->children()
+                ->arrayNode('feature_flag')
+                    ->info('FeatureFlag configuration')
+                    ->{$enableIfStandalone('symfony/feature-flag', FeatureCheckerInterface::class)}()
+                    ->fixXmlConfig('feature_flag')
+                ->end()
+            ->end();
+    }
 }
diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
@@ -79,6 +79,9 @@
 use Symfony\Component\EventDispatcher\Attribute\AsEventListener;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\ExpressionLanguage\ExpressionLanguage;
+use Symfony\Component\FeatureFlag\Attribute\AsFeature;
+use Symfony\Component\FeatureFlag\FeatureChecker;
+use Symfony\Component\FeatureFlag\Provider\ProviderInterface;
 use Symfony\Component\Filesystem\Filesystem;
 use Symfony\Component\Finder\Finder;
 use Symfony\Component\Finder\Glob;
@@ -169,6 +172,7 @@
 use Symfony\Component\RemoteEvent\Attribute\AsRemoteEventConsumer;
 use Symfony\Component\RemoteEvent\RemoteEvent;
 use Symfony\Component\Routing\Attribute\Route;
+use Symfony\Component\Routing\Router;
 use Symfony\Component\Scheduler\Attribute\AsCronTask;
 use Symfony\Component\Scheduler\Attribute\AsPeriodicTask;
 use Symfony\Component\Scheduler\Attribute\AsSchedule;
@@ -310,6 +314,7 @@ public function load(array $configs, ContainerBuilder $container): void
         $this->readConfigEnabled('property_access', $container, $config['property_access']);
         $this->readConfigEnabled('profiler', $container, $config['profiler']);
         $this->readConfigEnabled('workflows', $container, $config['workflows']);
+        $this->readConfigEnabled('feature_flag', $container, $config['feature_flag']);
 
         // A translator must always be registered (as support is included by
         // default in the Form and Validator component). If disabled, an identity
@@ -638,6 +643,13 @@ public function load(array $configs, ContainerBuilder $container): void
             $this->registerHtmlSanitizerConfiguration($config['html_sanitizer'], $container, $loader);
         }
 
+        if ($this->readConfigEnabled('feature_flag', $container, $config['feature_flag'])) {
+            if (!class_exists(FeatureChecker::class)) {
+                throw new LogicException('FeatureFlag support cannot be enabled as the FeatureFlag component is not installed. Try running "composer require symfony/feature-flag".');
+            }
+            $this->registerFeatureFlagConfiguration($config['feature_flag'], $container, $loader);
+        }
+
         if (ContainerBuilder::willBeAvailable('symfony/mime', MimeTypes::class, ['symfony/framework-bundle'])) {
             $loader->load('mime_type.php');
         }
@@ -1011,6 +1023,10 @@ private function registerProfilerConfiguration(array $config, ContainerBuilder $
             $loader->load('serializer_debug.php');
         }
 
+        if ($this->isInitializedConfigEnabled('feature_flag')) {
+            $loader->load('feature_flag_debug.php');
+        }
+
         $container->setParameter('profiler_listener.only_exceptions', $config['only_exceptions']);
         $container->setParameter('profiler_listener.only_main_requests', $config['only_main_requests']);
 
@@ -3428,6 +3444,45 @@ private function registerHtmlSanitizerConfiguration(array $config, ContainerBuil
         }
     }
 
+    private function registerFeatureFlagConfiguration(array $config, ContainerBuilder $container, PhpFileLoader $loader): void
+    {
+        $loader->load('feature_flag.php');
+
+        $container->registerForAutoconfiguration(ProviderInterface::class)
+            ->addTag('feature_flag.provider')
+        ;
+
+        $container->registerAttributeForAutoconfiguration(AsFeature::class,
+            static function (ChildDefinition $definition, AsFeature $attribute, \ReflectionClass|\ReflectionMethod $reflector): void {
+                $featureName = $attribute->name;
+
+                if ($reflector instanceof \ReflectionClass) {
+                    $className = $reflector->getName();
+                    $method = $attribute->method;
+
+                    $featureName ??= $className;
+                } else {
+                    $className = $reflector->getDeclaringClass()->getName();
+                    if (null !== $attribute->method && $reflector->getName() !== $attribute->method) {
+                        throw new \LogicException(\sprintf('Using the #[%s(method: "%s")] attribute on a method is not valid. Either remove the method value or move this to the top of the class (%s).', AsFeature::class, $attribute->method, $className));
+                    }
+
+                    $method = $reflector->getName();
+                    $featureName ??= "{$className}::{$method}";
+                }
+
+                $definition->addTag('feature_flag.feature', [
+                    'feature' => $featureName,
+                    'method' => $method,
+                ]);
+            },
+        );
+
+        if (ContainerBuilder::willBeAvailable('symfony/routing', Router::class, ['symfony/framework-bundle', 'symfony/routing'])) {
+            $loader->load('feature_flag_routing.php');
+        }
+    }
+
     public function getXsdValidationBasePath(): string|false
     {
         return \dirname(__DIR__).'/Resources/config/schema';

diff --git a/src/Symfony/Bundle/FrameworkBundle/FrameworkBundle.php b/src/Symfony/Bundle/FrameworkBundle/FrameworkBundle.php
@@ -15,6 +15,7 @@
 use Symfony\Bundle\FrameworkBundle\DependencyInjection\Compiler\AssetsContextPass;
 use Symfony\Bundle\FrameworkBundle\DependencyInjection\Compiler\ContainerBuilderDebugDumpPass;
 use Symfony\Bundle\FrameworkBundle\DependencyInjection\Compiler\ErrorLoggerCompilerPass;
+use Symfony\Bundle\FrameworkBundle\DependencyInjection\Compiler\FeatureFlagPass;
 use Symfony\Bundle\FrameworkBundle\DependencyInjection\Compiler\ProfilerPass;
 use Symfony\Bundle\FrameworkBundle\DependencyInjection\Compiler\RemoveUnusedSessionMarshallingHandlerPass;
 use Symfony\Bundle\FrameworkBundle\DependencyInjection\Compiler\TestServiceContainerRealRefPass;
@@ -190,6 +191,7 @@ public function build(ContainerBuilder $container): void
         $container->addCompilerPass(new VirtualRequestStackPass());
         $container->addCompilerPass(new TranslationUpdateCommandPass(), PassConfig::TYPE_BEFORE_REMOVING);
         $this->addCompilerPassIfExists($container, StreamablePass::class);
+        $container->addCompilerPass(new FeatureFlagPass());
 
         if ($container->getParameter('kernel.debug')) {
             $container->addCompilerPass(new AddDebugLogProcessorPass(), PassConfig::TYPE_BEFORE_OPTIMIZATION, 2);

diff --git a/src/Symfony/Bundle/FrameworkBundle/Resources/config/feature_flag.php b/src/Symfony/Bundle/FrameworkBundle/Resources/config/feature_flag.php
@@ -0,0 +1,41 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\DependencyInjection\Loader\Configurator;
+
+use Symfony\Component\FeatureFlag\FeatureChecker;
+use Symfony\Component\FeatureFlag\FeatureCheckerInterface;
+use Symfony\Component\FeatureFlag\Provider\ChainProvider;
+use Symfony\Component\FeatureFlag\Provider\InMemoryProvider;
+use Symfony\Component\FeatureFlag\Provider\ProviderInterface;
+
+return static function (ContainerConfigurator $container) {
+    $container->services()
+
+        ->set('feature_flag.provider.in_memory', InMemoryProvider::class)
+            ->args([
+                '$features' => abstract_arg('Defined in FeatureFlagPass.'),
+            ])
+            ->tag('feature_flag.provider')
+
+        ->set('feature_flag.provider', ChainProvider::class)
+            ->args([
+                '$providers' => tagged_iterator('feature_flag.provider'),
+            ])
+            ->alias(ProviderInterface::class, 'feature_flag.provider')
+
+        ->set('feature_flag.feature_checker', FeatureChecker::class)
+            ->args([
+                '$provider' => service('feature_flag.provider'),
+            ])
+            ->alias(FeatureCheckerInterface::class, 'feature_flag.feature_checker')
+    ;
+};