Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

core/lib/Drupal/Core/Validation/ConstraintManager.php

@@ -11,7 +11,7 @@ use Drupal\Component\Plugin\Discovery\StaticDiscoveryDecorator;
 use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Plugin\DefaultPluginManager;
-use Drupal\Core\StringTranslation\TranslationWrapper;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
 
 /**
  * Constraint plugin manager.
@@ -91,22 +91,22 @@ class ConstraintManager extends DefaultPluginManager {
    */
   public function registerDefinitions() {
     $this->getDiscovery()->setDefinition('Callback', array(
-      'label' => new TranslationWrapper('Callback'),
+      'label' => new TranslatableMarkup('Callback'),
       'class' => '\Symfony\Component\Validator\Constraints\Callback',
       'type' => FALSE,
     ));
     $this->getDiscovery()->setDefinition('Blank', array(
-      'label' => new TranslationWrapper('Blank'),
+      'label' => new TranslatableMarkup('Blank'),
       'class' => '\Symfony\Component\Validator\Constraints\Blank',
       'type' => FALSE,
     ));
     $this->getDiscovery()->setDefinition('NotBlank', array(
-      'label' => new TranslationWrapper('Not blank'),
+      'label' => new TranslatableMarkup('Not blank'),
       'class' => '\Symfony\Component\Validator\Constraints\NotBlank',
       'type' => FALSE,
     ));
     $this->getDiscovery()->setDefinition('Email', array(
-      'label' => new TranslationWrapper('Email'),
+      'label' => new TranslatableMarkup('Email'),
       'class' => '\Drupal\Core\Validation\Plugin\Validation\Constraint\EmailConstraint',
       'type' => array('string'),
     ));

core/lib/Drupal/Core/Validation/DrupalTranslator.php

@@ -7,7 +7,8 @@
 
 namespace Drupal\Core\Validation;
 
-use Symfony\Component\Translation\TranslatorInterface;
+use Drupal\Component\Render\MarkupInterface;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
 
 /**
  * Translates strings using Drupal's translation system.
@@ -27,8 +28,9 @@ class DrupalTranslator implements TranslatorInterface {
    * Implements \Symfony\Component\Translation\TranslatorInterface::trans().
    */
   public function trans($id, array $parameters = array(), $domain = NULL, $locale = NULL) {
-
-    return t($id, $this->processParameters($parameters), $this->getOptions($domain, $locale));
+    // If a TranslatableMarkup object is passed in as $id, return it since the
+    // message has already been translated.
+    return $id instanceof TranslatableMarkup ? $id : t($id, $this->processParameters($parameters), $this->getOptions($domain, $locale));
   }
 
   /**
@@ -41,6 +43,17 @@ class DrupalTranslator implements TranslatorInterface {
     if (!isset($ids[1])) {
       throw new \InvalidArgumentException(sprintf('The message "%s" cannot be pluralized, because it is missing a plural (e.g. "There is one apple|There are @count apples").', $id));
     }
+
+    // Normally, calls to formatPlural() need to use literal strings, like
+    //   formatPlural($count, '1 item', '@count items')
+    // so that the Drupal project POTX string extractor will correctly
+    // extract the strings for translation and save them in a format that
+    // formatPlural() can work with. However, this is a special case, because
+    // Drupal is supporting a constraint message format from Symfony. So
+    // although $id looks like a variable here, it is actually coming from a
+    // static string in a constraint class that the POTX extractor knows about
+    // and has processed to work with formatPlural(), so this specific call to
+    // formatPlural() will work correctly.
     return \Drupal::translation()->formatPlural($number, $ids[0], $ids[1], $this->processParameters($parameters), $this->getOptions($domain, $locale));
   }
 
@@ -64,8 +77,14 @@ class DrupalTranslator implements TranslatorInterface {
   protected function processParameters(array $parameters) {
     $return = array();
     foreach ($parameters as $key => $value) {
+      // We allow the values in the parameters to be safe string objects. This
+      // can be useful when we want to use parameter values that are
+      // TranslatableMarkup.
+      if ($value instanceof MarkupInterface) {
+        $value = (string) $value;
+      }
       if (is_object($value)) {
-        // t() does not work will objects being passed as replacement strings.
+        // t() does not work with objects being passed as replacement strings.
       }
       // Check for symfony replacement patterns in the form "{{ name }}".
       elseif (strpos($key, '{{ ') === 0 && strrpos($key, ' }}') == strlen($key) - 3) {

core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/PrimitiveTypeConstraintValidator.php

@@ -16,6 +16,7 @@ use Drupal\Core\TypedData\Type\IntegerInterface;
 use Drupal\Core\TypedData\Type\StringInterface;
 use Drupal\Core\TypedData\Type\UriInterface;
 use Drupal\Core\TypedData\Validation\TypedDataAwareValidatorTrait;
+use Drupal\Component\Render\MarkupInterface;
 use Symfony\Component\Validator\Constraint;
 use Symfony\Component\Validator\ConstraintValidator;
 
@@ -49,7 +50,7 @@ class PrimitiveTypeConstraintValidator extends ConstraintValidator {
     if ($typed_data instanceof IntegerInterface && filter_var($value, FILTER_VALIDATE_INT) === FALSE) {
       $valid = FALSE;
     }
-    if ($typed_data instanceof StringInterface && !is_scalar($value)) {
+    if ($typed_data instanceof StringInterface && !is_scalar($value) && !($value instanceof MarkupInterface)) {
       $valid = FALSE;
     }
     // Ensure that URIs comply with http://tools.ietf.org/html/rfc3986, which

core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/RegexConstraint.php

@@ -0,0 +1,32 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Validation\Plugin\Validation\Constraint\RegexConstraint.
+ */
+
+namespace Drupal\Core\Validation\Plugin\Validation\Constraint;
+
+use Symfony\Component\Validator\Constraints\Regex;
+
+/**
+ * Regex constraint.
+ *
+ * Overrides the symfony constraint to use Drupal-style replacement patterns.
+ *
+ * @Constraint(
+ *   id = "Regex",
+ *   label = @Translation("Regex", context = "Validation")
+ * )
+ */
+class RegexConstraint extends Regex {
+
+  public $message = 'This value is not valid.';
+
+  /**
+   * Overrides Range::validatedBy().
+   */
+  public function validatedBy() {
+    return '\Symfony\Component\Validator\Constraints\RegexValidator';
+  }
+}

core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/UniqueFieldConstraint.php

@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Validation\Plugin\Validation\Constraint\UniqueFieldConstraint.
+ */
+
+namespace Drupal\Core\Validation\Plugin\Validation\Constraint;
+
+use Symfony\Component\Validator\Constraint;
+
+/**
+ * Checks if an entity field has a unique value.
+ *
+ * @Constraint(
+ *   id = "UniqueField",
+ *   label = @Translation("Unique field constraint", context = "Validation"),
+ * )
+ */
+class UniqueFieldConstraint extends Constraint {
+
+  public $message = 'A @entity_type with @field_name %value already exists.';
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validatedBy() {
+    return '\Drupal\Core\Validation\Plugin\Validation\Constraint\UniqueFieldValueValidator';
+  }
+
+}

core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/UniqueFieldValueValidator.php

@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Validation\Plugin\Validation\Constraint;
 
+use Drupal\Component\Utility\Unicode;
 use Symfony\Component\Validator\Constraint;
 use Symfony\Component\Validator\ConstraintValidator;
 
@@ -37,7 +38,11 @@ class UniqueFieldValueValidator extends ConstraintValidator {
       ->execute();
 
     if ($value_taken) {
-      $this->context->addViolation($constraint->message, array("%value" => $item->value));
+      $this->context->addViolation($constraint->message, [
+        '%value' => $item->value,
+        '@entity_type' => $entity->getEntityType()->getLowercaseLabel(),
+        '@field_name' => Unicode::strtolower($items->getFieldDefinition()->getLabel()),
+      ]);
     }
   }
 }

core/lib/Drupal/Core/Validation/TranslatorInterface.php

@@ -0,0 +1,24 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Validation\TranslatorInterface.
+ */
+
+namespace Drupal\Core\Validation;
+
+use Symfony\Component\Translation\TranslatorInterface as SymfonyTranslatorInterface;
+
+/**
+ * Defines an interface used in validation.
+ *
+ * This extends the interface used by the Symfony validator in order to indicate
+ * that the Drupal code is actually independent from the Symfony translation
+ * component.
+ *
+ * @see https://github.com/symfony/symfony/pull/6189
+ * @see https://github.com/symfony/symfony/issues/15714
+ */
+interface TranslatorInterface extends SymfonyTranslatorInterface {
+
+}