[Validator] Add option for LANG="en_US.UTF-8"

LC_COLLATE="en_US.UTF-8"
LC_CTYPE="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_ALL= validator

src/Symfony/Component/Validator/Constraints/Locale.php

@@ -28,4 +28,5 @@ class Locale extends Constraint
     );
 
     public $message = 'This value is not a valid locale.';
+    public $canonicalize = false;
 }

src/Symfony/Component/Validator/Constraints/LocaleValidator.php

@@ -41,6 +41,9 @@ class LocaleValidator extends ConstraintValidator
         }
 
         $value = (string) $value;
+        if ($constraint->canonicalize) {
+            $value = \Locale::canonicalize($value);
+        }
         $locales = Intl::getLocaleBundle()->getLocaleNames();
         $aliases = Intl::getLocaleBundle()->getAliases();
 

src/Symfony/Component/Validator/Tests/Constraints/LocaleValidatorTest.php

@@ -90,4 +90,45 @@ class LocaleValidatorTest extends ConstraintValidatorTestCase
             array('foobar'),
         );
     }
+
+    /**
+     * @dataProvider getUncanonicalizedLocales
+     */
+    public function testInvalidLocalesWithoutCanonicalization(string $locale)
+    {
+        $constraint = new Locale(array(
+            'message' => 'myMessage',
+        ));
+
+        $this->validator->validate($locale, $constraint);
+
+        $this->buildViolation('myMessage')
+            ->setParameter('{{ value }}', '"'.$locale.'"')
+            ->setCode(Locale::NO_SUCH_LOCALE_ERROR)
+            ->assertRaised();
+    }
+
+    /**
+     * @dataProvider getUncanonicalizedLocales
+     */
+    public function testValidLocalesWithCanonicalization(string $locale)
+    {
+        $constraint = new Locale(array(
+            'message' => 'myMessage',
+            'canonicalize' => true,
+        ));
+
+        $this->validator->validate($locale, $constraint);
+
+        $this->assertNoViolation();
+    }
+
+    public function getUncanonicalizedLocales(): iterable
+    {
+        return array(
+            array('en-US'),
+            array('es-AR'),
+            array('fr_FR.utf8'),
+        );
+    }
 }