Include underlying connection error when transport connection fails

Author: clue

src/Query/TcpTransportExecutor.php

@@ -227,7 +227,19 @@ public function handleWritable()
         if ($this->readPending === false) {
             $name = @\stream_socket_get_name($this->socket, true);
             if ($name === false) {
-                $this->closeError('Connection to DNS server ' . $this->nameserver . ' rejected');
+                // Connection failed? Check socket error if available for underlying errno/errstr.
+                // @codeCoverageIgnoreStart
+                if (\function_exists('socket_import_stream')) {
+                    $socket = \socket_import_stream($this->socket);
+                    $errno = \socket_get_option($socket, \SOL_SOCKET, \SO_ERROR);
+                    $errstr = \socket_strerror($errno);
+                } else {
+                    $errno = \defined('SOCKET_ECONNREFUSED') ? \SOCKET_ECONNREFUSED : 111;
+                    $errstr = 'Connection refused';
+                }
+                // @codeCoverageIgnoreEnd
+
+                $this->closeError('Unable to connect to DNS server ' . $this->nameserver . ' (' . $errstr . ')', $errno);
                 return;
             }
 

tests/Query/TcpTransportExecutorTest.php

@@ -265,7 +265,8 @@ function ($e) use (&$exception) {
 
         /** @var \RuntimeException $exception */
         $this->assertInstanceOf('RuntimeException', $exception);
-        $this->assertEquals('DNS query for google.com (A) failed: Connection to DNS server tcp://127.0.0.1:1 rejected', $exception->getMessage());
+        $this->assertEquals('DNS query for google.com (A) failed: Unable to connect to DNS server tcp://127.0.0.1:1 (Connection refused)', $exception->getMessage());
+        $this->assertEquals(defined('SOCKET_ECONNREFUSED') ? SOCKET_ECONNREFUSED : 111, $exception->getCode());
     }
 
     public function testQueryStaysPendingWhenClientCanNotSendExcessiveMessageInOneChunk()