bug #32211 [Mailer] Fix error message when connecting to a stream rai…

…ses an error before connect() (fabpot)

This PR was merged into the 4.3 branch.

Discussion
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[Mailer] Fix error message when connecting to a stream raises an error before connect()

| Q             | A
| ------------- | ---
| Branch?       | 4.3
| Bug fix?      | yes
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | see swiftmailer/swiftmailer#1201
| License       | MIT
| Doc PR        | n/a

According to the PHP docs, "If the value returned in errno is 0 and the function returned FALSE, it is an indication that the error occurred before the connect() call.".

Using the `@` operator means that we get a generic error message without any clues about why connection cannot be done. Using an error handler allows to get the real issue.

Commits
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eb15bff [Mailer] fixed error message when connecting to a stream raises an error before connect()

src/Symfony/Component/Mailer/Tests/Transport/Smtp/Stream/SocketStreamTest.php

@@ -0,0 +1,49 @@
+<?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\Stream;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Mailer\Transport\Smtp\Stream\SocketStream;
+
+class SocketStreamTest extends TestCase
+{
+    /**
+     * @expectedException \Symfony\Component\Mailer\Exception\TransportException
+     * @expectedExceptionMessage Connection refused
+     */
+    public function testSocketErrorNoConnection()
+    {
+        $s = new SocketStream();
+        $s->setTimeout(0.1);
+        $s->setPort(9999);
+        $s->initialize();
+    }
+
+    /**
+     * @expectedException \Symfony\Component\Mailer\Exception\TransportException
+     * @expectedExceptionMessage no valid certs found cafile stream
+     */
+    public function testSocketErrorBeforeConnectError()
+    {
+        $s = new SocketStream();
+        $s->setStreamOptions([
+            'ssl' => [
+                // not a CA file :)
+                'cafile' => __FILE__,
+            ],
+        ]);
+        $s->setEncryption('ssl');
+        $s->setHost('smtp.gmail.com');
+        $s->setPort(465);
+        $s->initialize();
+    }
+}

src/Symfony/Component/Mailer/Transport/Smtp/Stream/SocketStream.php

@@ -144,10 +144,16 @@ public function initialize(): void
             $options['ssl']['crypto_method'] = $options['ssl']['crypto_method'] ?? STREAM_CRYPTO_METHOD_TLS_CLIENT | STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT | STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT;
         }
         $streamContext = stream_context_create($options);
-        $this->stream = @stream_socket_client($this->url, $errno, $errstr, $this->timeout, STREAM_CLIENT_CONNECT, $streamContext);
-        if (false === $this->stream) {
-            throw new TransportException(sprintf('Connection could not be established with host "%s": %s (%s)', $this->url, $errstr, $errno));
+
+        set_error_handler(function ($type, $msg) {
+            throw new TransportException(sprintf('Connection could not be established with host "%s": %s.', $this->url, $msg));
+        });
+        try {
+            $this->stream = stream_socket_client($this->url, $errno, $errstr, $this->timeout, STREAM_CLIENT_CONNECT, $streamContext);
+        } finally {
+            restore_error_handler();
         }
+
         stream_set_blocking($this->stream, true);
         stream_set_timeout($this->stream, $this->timeout);
         $this->in = &$this->stream;