bug #30995 [Mailer] allow user/pass on dsn while using failover/round…

…robin (scuben)

This PR was merged into the 4.3-dev branch.

Discussion
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[Mailer] allow user/pass on dsn while using failover/roundrobin

| Q             | A
| ------------- | ---
| Branch?       | master <!-- see below -->
| Bug fix?      | yes
| New feature?  | no <!-- don't forget to update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- don't forget to update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

this PR provides two things:
1. It is possible now to user `username` and `password` in a failover or round robin transport when using smtp
2. Fixed a type problem with `username` and `password` for the smtp transport as `getUsername()` cannot return `null` because of its signature but if no `username` is provided then the property would have been `null`. Fixed with setting an empty string as default. Same for `password`. (This was discovered by adding a test - yeah!)

Commits
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4518ac5 allow user/pass on dns while using failover/roundrobin and type fix for username/password

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

@@ -236,9 +236,11 @@ public function testFromDsnMailchimp()
 
     public function testFromDsnFailover()
     {
+        $user = 'user';
+        $pass = 'pass';
         $dispatcher = $this->createMock(EventDispatcherInterface::class);
         $logger = $this->createMock(LoggerInterface::class);
-        $transport = Transport::fromDsn('smtp://null || smtp://null || smtp://null', $dispatcher, null, $logger);
+        $transport = Transport::fromDsn('smtp://example.com || smtp://'.urlencode($user).'@example.com || smtp://'.urlencode($user).':'.urlencode($pass).'@example.com', $dispatcher, null, $logger);
         $this->assertInstanceOf(Transport\FailoverTransport::class, $transport);
         $p = new \ReflectionProperty(Transport\RoundRobinTransport::class, 'transports');
         $p->setAccessible(true);
@@ -247,6 +249,12 @@ public function testFromDsnFailover()
         foreach ($transports as $transport) {
             $this->assertProperties($transport, $dispatcher, $logger);
         }
+        $this->assertSame('', $transports[0]->getUsername());
+        $this->assertSame('', $transports[0]->getPassword());
+        $this->assertSame($user, $transports[1]->getUsername());
+        $this->assertSame('', $transports[1]->getPassword());
+        $this->assertSame($user, $transports[2]->getUsername());
+        $this->assertSame($pass, $transports[2]->getPassword());
     }
 
     public function testFromDsnRoundRobin()

src/Symfony/Component/Mailer/Transport.php

@@ -171,7 +171,17 @@ private static function createTransport(string $dsn, EventDispatcherInterface $d
                 throw new LogicException(sprintf('The "%s" scheme is not supported for mailer "%s".', $parsedDsn['scheme'], $parsedDsn['host']));
             default:
                 if ('smtp' === $parsedDsn['scheme']) {
-                    return new Transport\Smtp\EsmtpTransport($parsedDsn['host'], $parsedDsn['port'] ?? 25, $query['encryption'] ?? null, $query['auth_mode'] ?? null, $dispatcher, $logger);
+                    $transport = new Transport\Smtp\EsmtpTransport($parsedDsn['host'], $parsedDsn['port'] ?? 25, $query['encryption'] ?? null, $query['auth_mode'] ?? null, $dispatcher, $logger);
+
+                    if ($user) {
+                        $transport->setUsername($user);
+                    }
+
+                    if ($pass) {
+                        $transport->setPassword($pass);
+                    }
+
+                    return $transport;
                 }
 
                 throw new LogicException(sprintf('The "%s" mailer is not supported.', $parsedDsn['host']));

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

@@ -29,8 +29,8 @@
 class EsmtpTransport extends SmtpTransport
 {
     private $authenticators = [];
-    private $username;
-    private $password;
+    private $username = '';
+    private $password = '';
     private $authMode;
 
     public function __construct(string $host = 'localhost', int $port = 25, string $encryption = null, string $authMode = null, EventDispatcherInterface $dispatcher = null, LoggerInterface $logger = null)