[Validator] Add the When constraint and validator

Author: wuchen90

DependencyInjection/FrameworkExtension.php

@@ -221,6 +221,7 @@
 use Symfony\Component\Translation\Translator;
 use Symfony\Component\Uid\Factory\UuidFactory;
 use Symfony\Component\Uid\UuidV4;
+use Symfony\Component\Validator\Constraints\WhenValidator;
 use Symfony\Component\Validator\ConstraintValidatorInterface;
 use Symfony\Component\Validator\Mapping\Loader\PropertyInfoLoader;
 use Symfony\Component\Validator\ObjectInitializerInterface;
@@ -1570,6 +1571,10 @@ private function registerValidationConfiguration(array $config, ContainerBuilder
         if (!class_exists(ExpressionLanguage::class)) {
             $container->removeDefinition('validator.expression_language');
         }
+
+        if (!class_exists(WhenValidator::class)) {
+            $container->removeDefinition('validator.when');
+        }
     }
 
     private function registerValidatorMapping(ContainerBuilder $container, array $config, array &$files)

Resources/config/validator.php

@@ -17,6 +17,7 @@
 use Symfony\Component\Validator\Constraints\EmailValidator;
 use Symfony\Component\Validator\Constraints\ExpressionValidator;
 use Symfony\Component\Validator\Constraints\NotCompromisedPasswordValidator;
+use Symfony\Component\Validator\Constraints\WhenValidator;
 use Symfony\Component\Validator\ContainerConstraintValidatorFactory;
 use Symfony\Component\Validator\Mapping\Loader\PropertyInfoLoader;
 use Symfony\Component\Validator\Validation;
@@ -95,6 +96,12 @@
                 'alias' => NotCompromisedPasswordValidator::class,
             ])
 
+        ->set('validator.when', WhenValidator::class)
+            ->args([service('validator.expression_language')->nullOnInvalid()])
+            ->tag('validator.constraint_validator', [
+                'alias' => WhenValidator::class,
+            ])
+
         ->set('validator.property_info_loader', PropertyInfoLoader::class)
             ->args([
                 service('property_info'),