How to use RFC-invalid email addresses used by Japanese Cell carriers, DoCoMo and EZWeb using SwiftMailer

env.php

Swift::init(function() {
	Swift_DependencyContainer::getInstance()
		->register('mime.grammar')
        	->asSharedInstanceOf('InvalidMimeGrammar');
        
        // ... other settings
});

InvalidMimeGrammar.php

<?php

class InvalidMimeGrammar extends \Swift_Mime_Grammar {
    /**
     * Get the grammar defined for $name token.
     * @param string $name exactly as written in the RFC
     * @return string
     */
    public function getDefinition($name)
    {
        switch ($name) {
            case 'addr-spec':
                $spec = parent::getDefinition($name);

                $fuzzy_domains = array(
                    'docomo\.ne\.jp',
                    'ezweb\.ne\.jp',
                );

                $atext = $this->getDefinition('atext');
                $CFWS = $this->getDefinition('CFWS');
                $invalid_dot_atom_text = '(?:\.*'. $atext. '+'. '(\.+'. $atext. '+)*\.*)';
                $invalid_dot_atom = '(?:'. $CFWS. '?'. $invalid_dot_atom_text. '+'. $CFWS. '?)';
                $quoted_string = $this->getDefinition('quoted-string');

                $local_part = '(?:'. $invalid_dot_atom. '|'. $quoted_string. ')';
                $domain_part = '(?:'. implode('|', $fuzzy_domains). ')';

                $spec = '(?:'. $spec. '|'. $local_part. '@'. $domain_part. ')';
                return $spec;

            default:
                return parent::getDefinition($name);
        }
    }
}

InvalidMimeGrammarTest.php

<?php

class InvalidMimeGrammarTest extends \PHPUnit_Framework_TestCase {
    /**
     * @dataProvider invalidJapaneseKetaiAddresses
     */
    public function testMimeGrammar($address, $expected)
    {
        $grammar = \Swift_DependencyContainer::getInstance()->lookup('mime.grammar');

        $result = preg_match('/^'.$grammar->getDefinition('addr-spec').'$/D', $address);
        $this->assertEquals($expected, $result);
    }

    public function invalidJapaneseKetaiAddresses() {
        return array(
            array('[email protected]', true),
            array('[email protected]', true),
            array('[email protected]', false),
            array('[email protected]', true),
            array('[email protected]', false),
            array('[email protected]', true),
            array('[email protected]', false),
            array('[email protected]', true),
        );
    }
}