Merge branch '4.4'

* 4.4:
  [PhpUnitBridge] fix internal annotation
  [Mime] added AbstractPart::asDebugString()
  [Mailer] added a name to the transport
  [Mailer] added missing entry in the CHANGELOG
  [FrameworkBundle] add config translator cache_dir
  [Yaml] Add flag to dump NULL as ~

src/Symfony/Bridge/PhpUnit/Legacy/PolyfillAssertTrait.php

@@ -17,7 +17,7 @@ use PHPUnit\Framework\Constraint\StringContains;
 use PHPUnit\Framework\Constraint\TraversableContains;
 
 /**
- * @internal
+ * This trait is @internal
  */
 trait PolyfillAssertTrait
 {

src/Symfony/Bridge/PhpUnit/Legacy/PolyfillTestCaseTrait.php

@@ -15,7 +15,7 @@ use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 
 /**
- * @internal
+ * This trait is @internal
  */
 trait PolyfillTestCaseTrait
 {

src/Symfony/Bridge/PhpUnit/bin/simple-phpunit.php

@@ -156,12 +156,6 @@ if (!file_exists("$PHPUNIT_DIR/$PHPUNIT_VERSION_DIR/phpunit") || $configurationH
     $alteredCode = preg_replace('/abstract class (?:Assert|PHPUnit_Framework_Assert)[^\{]+\{/', '$0 '.PHP_EOL."    use \Symfony\Bridge\PhpUnit\Legacy\PolyfillAssertTrait;", $alteredCode, 1);
     file_put_contents($alteredFile, $alteredCode);
 
-    // remove internal annotation from polyfill
-    foreach (array('PolyfillTestCaseTrait', 'PolyfillAssertTrait') as $polyfill) {
-        $traitFile = "./vendor/symfony/phpunit-bridge/Legacy/$polyfill.php";
-        file_put_contents($traitFile, str_replace(' * @internal', '', file_get_contents($traitFile)));
-    }
-
     file_put_contents('phpunit', <<<'EOPHP'
 <?php
 

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php

@@ -652,6 +652,7 @@ class Configuration implements ConfigurationInterface
                         ->end()
                         ->booleanNode('logging')->defaultValue(false)->end()
                         ->scalarNode('formatter')->defaultValue('translator.formatter.default')->end()
+                        ->scalarNode('cache_dir')->defaultValue('%kernel.cache_dir%/translations')->end()
                         ->scalarNode('default_path')
                             ->info('The default path used to load translations')
                             ->defaultValue('%kernel.project_dir%/translations')

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php

@@ -992,6 +992,10 @@ class FrameworkExtension extends Extension
         $translator = $container->findDefinition('translator.default');
         $translator->addMethodCall('setFallbackLocales', [$config['fallbacks'] ?: [$defaultLocale]]);
 
+        $defaultOptions = $translator->getArgument(4);
+        $defaultOptions['cache_dir'] = $config['cache_dir'];
+        $translator->setArgument(4, $defaultOptions);
+
         $container->setParameter('translator.logging', $config['logging']);
         $container->setParameter('translator.default_path', $config['default_path']);
 

src/Symfony/Bundle/FrameworkBundle/Resources/config/schema/symfony-1.0.xsd

@@ -173,6 +173,7 @@
         <xsd:attribute name="fallback" type="xsd:string" />
         <xsd:attribute name="logging" type="xsd:boolean" />
         <xsd:attribute name="formatter" type="xsd:string" />
+        <xsd:attribute name="cache-dir" type="xsd:string" />
     </xsd:complexType>
 
     <xsd:complexType name="validation">

src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/ConfigurationTest.php

@@ -225,6 +225,7 @@ class ConfigurationTest extends TestCase
             'translator' => [
                 'enabled' => !class_exists(FullStack::class),
                 'fallbacks' => [],
+                'cache_dir' => '%kernel.cache_dir%/translations',
                 'logging' => false,
                 'formatter' => 'translator.formatter.default',
                 'paths' => [],

src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/full.php

@@ -46,6 +46,7 @@ $container->loadFromExtension('framework', [
         'enabled' => true,
         'fallback' => 'fr',
         'paths' => ['%kernel.project_dir%/Fixtures/translations'],
+        'cache_dir' => '%kernel.cache_dir%/translations',
     ],
     'validation' => [
         'enabled' => true,

src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/translator_cache_dir_disabled.php

@@ -0,0 +1,7 @@
+<?php
+
+$container->loadFromExtension('framework', [
+    'translator' => [
+        'cache_dir' => null,
+    ],
+]);

src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/xml/full.xml

@@ -26,7 +26,7 @@
             </framework:format>
         </framework:request>
         <framework:assets version="v1" />
-        <framework:translator enabled="true" fallback="fr" logging="true">
+        <framework:translator enabled="true" fallback="fr" logging="true" cache-dir="%kernel.cache_dir%/translations">
             <framework:path>%kernel.project_dir%/Fixtures/translations</framework:path>
         </framework:translator>
         <framework:validation enabled="true" />

src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/xml/translator_cache_dir_disabled.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" ?>
+
+<container xmlns="http://symfony.com/schema/dic/services"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns:framework="http://symfony.com/schema/dic/symfony"
+    xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd
+                        http://symfony.com/schema/dic/symfony https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">
+
+    <framework:config secret="s3cr3t">
+        <framework:translator enabled="true" fallback="fr" logging="true" cache-dir="null" />
+    </framework:config>
+</container>

src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/yml/full.yml

@@ -36,6 +36,7 @@ framework:
         enabled:  true
         fallback: fr
         default_path: '%kernel.project_dir%/translations'
+        cache_dir: '%kernel.cache_dir%/translations'
         paths: ['%kernel.project_dir%/Fixtures/translations']
     validation:
         enabled: true

src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/yml/translator_cache_dir_disabled.yml

@@ -0,0 +1,3 @@
+framework:
+    translator:
+        cache_dir: ~

src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTest.php

@@ -54,6 +54,7 @@ use Symfony\Component\Translation\DependencyInjection\TranslatorPass;
 use Symfony\Component\Validator\DependencyInjection\AddConstraintValidatorsPass;
 use Symfony\Component\Validator\Mapping\Loader\PropertyInfoLoader;
 use Symfony\Component\Workflow;
+use Symfony\Contracts\Translation\TranslatorInterface;
 
 abstract class FrameworkExtensionTest extends TestCase
 {
@@ -683,6 +684,9 @@ abstract class FrameworkExtensionTest extends TestCase
         $this->assertEquals('translator.default', (string) $container->getAlias('translator'), '->registerTranslatorConfiguration() redefines translator service from identity to real translator');
         $options = $container->getDefinition('translator.default')->getArgument(4);
 
+        $this->assertArrayHasKey('cache_dir', $options);
+        $this->assertSame($container->getParameter('kernel.cache_dir').'/translations', $options['cache_dir']);
+
         $files = array_map('realpath', $options['resource_files']['en']);
         $ref = new \ReflectionClass('Symfony\Component\Validator\Validation');
         $this->assertContains(
@@ -739,6 +743,13 @@ abstract class FrameworkExtensionTest extends TestCase
         $this->assertEquals(['en', 'fr'], $calls[1][1][0]);
     }
 
+    public function testTranslatorCacheDirDisabled()
+    {
+        $container = $this->createContainerFromFile('translator_cache_dir_disabled');
+        $options = $container->getDefinition('translator.default')->getArgument(4);
+        $this->assertNull($options['cache_dir']);
+    }
+
     public function testValidation()
     {
         $container = $this->createContainerFromFile('full');

src/Symfony/Bundle/FrameworkBundle/Tests/Functional/MailerTest.php

@@ -42,6 +42,11 @@ class MailerTest extends AbstractWebTestCase
                 $this->onDoSend = $onDoSend;
             }
 
+            public function getName(): string
+            {
+                return 'dummy://local';
+            }
+
             protected function doSend(SentMessage $message): void
             {
                 $onDoSend = $this->onDoSend;

src/Symfony/Bundle/FrameworkBundle/composer.json

@@ -73,6 +73,7 @@
         "symfony/dom-crawler": "<4.4",
         "symfony/form": "<4.4",
         "symfony/lock": "<4.4",
+        "symfony/mailer": "<4.4",
         "symfony/messenger": "<4.4",
         "symfony/property-info": "<4.4",
         "symfony/serializer": "<4.4",

src/Symfony/Component/Mailer/Bridge/Amazon/Transport/SesApiTransport.php

@@ -43,6 +43,11 @@ class SesApiTransport extends AbstractApiTransport
         parent::__construct($client, $dispatcher, $logger);
     }
 
+    public function getName(): string
+    {
+        return sprintf('api://%s@ses?region=%s', $this->accessKey, $this->region);
+    }
+
     protected function doSendApi(Email $email, SmtpEnvelope $envelope): ResponseInterface
     {
         $date = gmdate('D, d M Y H:i:s e');

src/Symfony/Component/Mailer/Bridge/Amazon/Transport/SesHttpTransport.php

@@ -42,6 +42,11 @@ class SesHttpTransport extends AbstractHttpTransport
         parent::__construct($client, $dispatcher, $logger);
     }
 
+    public function getName(): string
+    {
+        return sprintf('http://%s@ses?region=%s', $this->accessKey, $this->region);
+    }
+
     protected function doSendHttp(SentMessage $message): ResponseInterface
     {
         $date = gmdate('D, d M Y H:i:s e');

src/Symfony/Component/Mailer/Bridge/Mailchimp/Transport/MandrillApiTransport.php

@@ -36,6 +36,11 @@ class MandrillApiTransport extends AbstractApiTransport
         parent::__construct($client, $dispatcher, $logger);
     }
 
+    public function getName(): string
+    {
+        return sprintf('api://mandrill');
+    }
+
     protected function doSendApi(Email $email, SmtpEnvelope $envelope): ResponseInterface
     {
         $response = $this->client->request('POST', self::ENDPOINT, [

src/Symfony/Component/Mailer/Bridge/Mailchimp/Transport/MandrillHttpTransport.php

@@ -34,6 +34,11 @@ class MandrillHttpTransport extends AbstractHttpTransport
         parent::__construct($client, $dispatcher, $logger);
     }
 
+    public function getName(): string
+    {
+        return sprintf('http://mandrill');
+    }
+
     protected function doSendHttp(SentMessage $message): ResponseInterface
     {
         $envelope = $message->getEnvelope();

src/Symfony/Component/Mailer/Bridge/Mailgun/Transport/MailgunApiTransport.php

@@ -41,6 +41,11 @@ class MailgunApiTransport extends AbstractApiTransport
         parent::__construct($client, $dispatcher, $logger);
     }
 
+    public function getName(): string
+    {
+        return sprintf('api://%s@mailgun?region=%s', $this->domain, $this->region);
+    }
+
     protected function doSendApi(Email $email, SmtpEnvelope $envelope): ResponseInterface
     {
         $body = new FormDataPart($this->getPayload($email, $envelope));

src/Symfony/Component/Mailer/Bridge/Mailgun/Transport/MailgunHttpTransport.php

@@ -40,6 +40,11 @@ class MailgunHttpTransport extends AbstractHttpTransport
         parent::__construct($client, $dispatcher, $logger);
     }
 
+    public function getName(): string
+    {
+        return sprintf('http://%s@mailgun?region=%s', $this->domain, $this->region);
+    }
+
     protected function doSendHttp(SentMessage $message): ResponseInterface
     {
         $body = new FormDataPart([

src/Symfony/Component/Mailer/Bridge/Postmark/Transport/PostmarkApiTransport.php

@@ -36,6 +36,11 @@ class PostmarkApiTransport extends AbstractApiTransport
         parent::__construct($client, $dispatcher, $logger);
     }
 
+    public function getName(): string
+    {
+        return sprintf('api://postmark');
+    }
+
     protected function doSendApi(Email $email, SmtpEnvelope $envelope): ResponseInterface
     {
         $response = $this->client->request('POST', self::ENDPOINT, [

src/Symfony/Component/Mailer/Bridge/Sendgrid/Transport/SendgridApiTransport.php

@@ -37,6 +37,11 @@ class SendgridApiTransport extends AbstractApiTransport
         parent::__construct($client, $dispatcher, $logger);
     }
 
+    public function getName(): string
+    {
+        return sprintf('api://sendgrid');
+    }
+
     protected function doSendApi(Email $email, SmtpEnvelope $envelope): ResponseInterface
     {
         $response = $this->client->request('POST', self::ENDPOINT, [

src/Symfony/Component/Mailer/CHANGELOG.md

@@ -4,12 +4,14 @@ CHANGELOG
 4.4.0
 -----
 
+ * [BC BREAK] `TransportInterface` has a new `getName()` method
  * [BC BREAK] Classes `AbstractApiTransport` and `AbstractHttpTransport` moved under `Transport` sub-namespace.
  * [BC BREAK] Transports depend on `Symfony\Contracts\EventDispatcher\EventDispatcherInterface`
    instead of `Symfony\Component\EventDispatcher\EventDispatcherInterface`.
  * Added possibility to register custom transport for dsn by implementing
    `Symfony\Component\Mailer\Transport\TransportFactoryInterface` and tagging with `mailer.transport_factory` tag in DI.
  * Added `Symfony\Component\Mailer\Test\TransportFactoryTestCase` to ease testing custom transport factories.
+ * Added `SentMessage::getDebug()` and `TransportExceptionInterface::getDebug` to help debugging
 
 4.3.0
 -----

src/Symfony/Component/Mailer/Test/TransportFactoryTestCase.php

@@ -69,6 +69,9 @@ abstract class TransportFactoryTestCase extends TestCase
         $factory = $this->getFactory();
 
         $this->assertEquals($transport, $factory->create($dsn));
+        if ('smtp' !== $dsn->getScheme()) {
+            $this->assertStringMatchesFormat($dsn->getScheme().'://%S'.$dsn->getHost().'%S', $transport->getName());
+        }
     }
 
     /**

src/Symfony/Component/Mailer/Tests/Transport/FailoverTransportTest.php

@@ -29,6 +29,16 @@ class FailoverTransportTest extends TestCase
         new FailoverTransport([]);
     }
 
+    public function testGetName()
+    {
+        $t1 = $this->createMock(TransportInterface::class);
+        $t1->expects($this->once())->method('getName')->willReturn('t1://local');
+        $t2 = $this->createMock(TransportInterface::class);
+        $t2->expects($this->once())->method('getName')->willReturn('t2://local');
+        $t = new FailoverTransport([$t1, $t2]);
+        $this->assertEquals('t1://local || t2://local', $t->getName());
+    }
+
     public function testSendFirstWork()
     {
         $t1 = $this->createMock(TransportInterface::class);

src/Symfony/Component/Mailer/Tests/Transport/NullTransportTest.php

@@ -0,0 +1,24 @@
+<?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\Mailer\Tests\Transport;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Mailer\Transport\NullTransport;
+
+class NullTransportTest extends TestCase
+{
+    public function testName()
+    {
+        $t = new NullTransport();
+        $this->assertEquals('smtp://null', $t->getName());
+    }
+}

src/Symfony/Component/Mailer/Tests/Transport/RoundRobinTransportTest.php

@@ -28,6 +28,16 @@ class RoundRobinTransportTest extends TestCase
         new RoundRobinTransport([]);
     }
 
+    public function testGetName()
+    {
+        $t1 = $this->createMock(TransportInterface::class);
+        $t1->expects($this->once())->method('getName')->willReturn('t1://local');
+        $t2 = $this->createMock(TransportInterface::class);
+        $t2->expects($this->once())->method('getName')->willReturn('t2://local');
+        $t = new RoundRobinTransport([$t1, $t2]);
+        $this->assertEquals('t1://local && t2://local', $t->getName());
+    }
+
     public function testSendAlternate()
     {
         $t1 = $this->createMock(TransportInterface::class);

src/Symfony/Component/Mailer/Tests/Transport/SendmailTransportTest.php

@@ -0,0 +1,24 @@
+<?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\Mailer\Tests\Transport;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Mailer\Transport\SendmailTransport;
+
+class SendmailTransportTest extends TestCase
+{
+    public function testName()
+    {
+        $t = new SendmailTransport();
+        $this->assertEquals('smtp://sendmail', $t->getName());
+    }
+}

src/Symfony/Component/Mailer/Tests/Transport/Smtp/SmtpTransportTest.php

@@ -0,0 +1,28 @@
+<?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\Mailer\Tests\Transport\Smtp;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Mailer\Transport\Smtp\SmtpTransport;
+use Symfony\Component\Mailer\Transport\Smtp\Stream\SocketStream;
+
+class SmtpTransportTest extends TestCase
+{
+    public function testName()
+    {
+        $t = new SmtpTransport();
+        $this->assertEquals('smtp://localhost:25', $t->getName());
+
+        $t = new SmtpTransport((new SocketStream())->setHost('127.0.0.1')->setPort(2525));
+        $this->assertEquals('smtp://127.0.0.1:2525', $t->getName());
+    }
+}

src/Symfony/Component/Mailer/Tests/TransportTest.php

@@ -68,6 +68,11 @@ class DummyTransport implements Transport\TransportInterface
     {
         throw new \BadMethodCallException('This method newer should be called.');
     }
+
+    public function getName(): string
+    {
+        return sprintf('dummy://local');
+    }
 }
 
 class DummyTransportFactory implements Transport\TransportFactoryInterface

src/Symfony/Component/Mailer/Transport/AbstractTransport.php

@@ -39,6 +39,8 @@ abstract class AbstractTransport implements TransportInterface
         $this->logger = $logger ?: new NullLogger();
     }
 
+    abstract public function getName(): string;
+
     /**
      * Sets the maximum number of messages to send per second (0 to disable).
      */

src/Symfony/Component/Mailer/Transport/FailoverTransport.php

@@ -28,4 +28,9 @@ class FailoverTransport extends RoundRobinTransport
 
         return $this->currentTransport;
     }
+
+    protected function getNameSymbol(): string
+    {
+        return '||';
+    }
 }

src/Symfony/Component/Mailer/Transport/NullTransport.php

@@ -23,4 +23,9 @@ final class NullTransport extends AbstractTransport
     protected function doSend(SentMessage $message): void
     {
     }
+
+    public function getName(): string
+    {
+        return 'smtp://null';
+    }
 }

src/Symfony/Component/Mailer/Transport/RoundRobinTransport.php

@@ -56,6 +56,13 @@ class RoundRobinTransport implements TransportInterface
         throw new TransportException('All transports failed.');
     }
 
+    public function getName(): string
+    {
+        return implode(' '.$this->getNameSymbol().' ', array_map(function (TransportInterface $transport) {
+            return $transport->getName();
+        }, $this->transports));
+    }
+
     /**
      * Rotates the transport list around and returns the first instance.
      */
@@ -90,6 +97,11 @@ class RoundRobinTransport implements TransportInterface
         return $this->deadTransports->contains($transport);
     }
 
+    protected function getNameSymbol(): string
+    {
+        return '&&';
+    }
+
     private function moveCursor(int $cursor): int
     {
         return ++$cursor >= \count($this->transports) ? 0 : $cursor;

src/Symfony/Component/Mailer/Transport/SendmailTransport.php

@@ -73,6 +73,11 @@ class SendmailTransport extends AbstractTransport
         return parent::send($message, $envelope);
     }
 
+    public function getName(): string
+    {
+        return $this->transport->getName();
+    }
+
     protected function doSend(SentMessage $message): void
     {
         $this->getLogger()->debug(sprintf('Email transport "%s" starting', __CLASS__));

src/Symfony/Component/Mailer/Transport/Smtp/SmtpTransport.php

@@ -126,6 +126,15 @@ class SmtpTransport extends AbstractTransport
         return $message;
     }
 
+    public function getName(): string
+    {
+        if ($this->stream instanceof SocketStream) {
+            return sprintf('smtp://%s:%d', $this->stream->getHost(), $this->stream->getPort());
+        }
+
+        return sprintf('smtp://sendmail');
+    }
+
     /**
      * Runs a command against the stream, expecting the given response codes.
      *

src/Symfony/Component/Mailer/Transport/TransportInterface.php

@@ -30,4 +30,6 @@ interface TransportInterface
      * @throws TransportExceptionInterface
      */
     public function send(RawMessage $message, SmtpEnvelope $envelope = null): ?SentMessage;
+
+    public function getName(): string;
 }

src/Symfony/Component/Mime/CHANGELOG.md

@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+4.4.0
+-----
+
+ * Added `AbstractPart::asDebugString()`
+
 4.3.3
 -----
 

src/Symfony/Component/Mime/Part/AbstractMultipartPart.php

@@ -74,6 +74,20 @@ abstract class AbstractMultipartPart extends AbstractPart
         yield '--'.$this->getBoundary()."--\r\n";
     }
 
+    public function asDebugString(): string
+    {
+        $str = parent::asDebugString();
+        foreach ($this->getParts() as $part) {
+            $lines = explode("\n", $part->asDebugString());
+            $str .= "\n  └ ".array_shift($lines);
+            foreach ($lines as $line) {
+                $str .= "\n  |".$line;
+            }
+        }
+
+        return $str;
+    }
+
     private function getBoundary(): string
     {
         if (null === $this->boundary) {

src/Symfony/Component/Mime/Part/AbstractPart.php

@@ -50,6 +50,11 @@ abstract class AbstractPart
         yield from $this->bodyToIterable();
     }
 
+    public function asDebugString(): string
+    {
+        return $this->getMediaType().'/'.$this->getMediaSubtype();
+    }
+
     abstract public function bodyToString(): string;
 
     abstract public function bodyToIterable(): iterable;

src/Symfony/Component/Mime/Part/DataPart.php

@@ -103,6 +103,16 @@ class DataPart extends TextPart
         return $headers;
     }
 
+    public function asDebugString(): string
+    {
+        $str = parent::asDebugString();
+        if (null !== $this->filename) {
+            $str .= ' filename: '.$this->filename;
+        }
+
+        return $str;
+    }
+
     private function generateContentId(): string
     {
         return bin2hex(random_bytes(16)).'@symfony';

src/Symfony/Component/Mime/Part/TextPart.php

@@ -144,6 +144,19 @@ class TextPart extends AbstractPart
         return $headers;
     }
 
+    public function asDebugString(): string
+    {
+        $str = parent::asDebugString();
+        if (null !== $this->charset) {
+            $str .= ' charset: '.$this->charset;
+        }
+        if (null !== $this->disposition) {
+            $str .= ' disposition: '.$this->disposition;
+        }
+
+        return $str;
+    }
+
     private function getEncoder(): ContentEncoderInterface
     {
         if ('8bit' === $this->encoding) {

src/Symfony/Component/Yaml/CHANGELOG.md

@@ -6,6 +6,11 @@ CHANGELOG
 
  * Removed support for mappings inside multi-line strings.
 
+4.4.0
+-----
+
+ * Added support to dump `null` as `~` by using the `Yaml::DUMP_NULL_AS_TILDE` flag.
+
 4.3.0
 -----
 

src/Symfony/Component/Yaml/Inline.php

@@ -33,6 +33,7 @@ class Inline
     private static $objectSupport = false;
     private static $objectForMap = false;
     private static $constantSupport = false;
+    private static $nullAsTilde = false;
 
     public static function initialize(int $flags, int $parsedLineNumber = null, string $parsedFilename = null)
     {
@@ -40,6 +41,7 @@ class Inline
         self::$objectSupport = (bool) (Yaml::PARSE_OBJECT & $flags);
         self::$objectForMap = (bool) (Yaml::PARSE_OBJECT_FOR_MAP & $flags);
         self::$constantSupport = (bool) (Yaml::PARSE_CONSTANT & $flags);
+        self::$nullAsTilde = (bool) (Yaml::DUMP_NULL_AS_TILDE & $flags);
         self::$parsedFilename = $parsedFilename;
 
         if (null !== $parsedLineNumber) {
@@ -124,7 +126,7 @@ class Inline
                     throw new DumpException(sprintf('Unable to dump PHP resources in a YAML file ("%s").', get_resource_type($value)));
                 }
 
-                return 'null';
+                return self::dumpNull($flags);
             case $value instanceof \DateTimeInterface:
                 return $value->format('c');
             case \is_object($value):
@@ -150,11 +152,11 @@ class Inline
                     throw new DumpException('Object support when dumping a YAML file has been disabled.');
                 }
 
-                return 'null';
+                return self::dumpNull($flags);
             case \is_array($value):
                 return self::dumpArray($value, $flags);
             case null === $value:
-                return 'null';
+                return self::dumpNull($flags);
             case true === $value:
                 return 'true';
             case false === $value:
@@ -251,6 +253,15 @@ class Inline
         return sprintf('{ %s }', implode(', ', $output));
     }
 
+    private static function dumpNull(int $flags): string
+    {
+        if (Yaml::DUMP_NULL_AS_TILDE & $flags) {
+            return '~';
+        }
+
+        return 'null';
+    }
+
     /**
      * Parses a YAML scalar.
      *

src/Symfony/Component/Yaml/Tests/DumperTest.php

@@ -504,6 +504,11 @@ YAML;
         $this->expectExceptionMessage('The indentation must be greater than zero');
         new Dumper(-4);
     }
+
+    public function testDumpNullAsTilde()
+    {
+        $this->assertSame('{ foo: ~ }', $this->dumper->dump(['foo' => null], 0, 0, Yaml::DUMP_NULL_AS_TILDE));
+    }
 }
 
 class A

src/Symfony/Component/Yaml/Yaml.php

@@ -33,6 +33,7 @@ class Yaml
     const PARSE_CONSTANT = 256;
     const PARSE_CUSTOM_TAGS = 512;
     const DUMP_EMPTY_ARRAY_AS_SEQUENCE = 1024;
+    const DUMP_NULL_AS_TILDE = 2048;
 
     /**
      * Parses a YAML file into a PHP value.