Improve promise cancellation and clean up any garbage references

Author: clue

composer.json

@@ -16,7 +16,7 @@
     "require": {
         "php": ">=5.3",
         "react/promise": "^2.1 || ^1.2",
-        "react/socket": "^1.0 || ^0.8.6"
+        "react/socket": "^1.1"
     },
     "require-dev": {
         "phpunit/phpunit": "^6.0 || ^5.7 || ^4.8.35",

src/Client.php

@@ -157,19 +157,53 @@ public function connect($uri)
             $socksUri .= '#' . $parts['fragment'];
         }
 
-        $that = $this;
+        // start TCP/IP connection to SOCKS server
+        $connecting = $this->connector->connect($socksUri);
+
+        $deferred = new Deferred(function ($_, $reject) use ($connecting) {
+            $reject(new RuntimeException(
+                'Connection cancelled while waiting for proxy (ECONNABORTED)',
+                defined('SOCKET_ECONNABORTED') ? SOCKET_ECONNABORTED : 103
+            ));
+
+            // either close active connection or cancel pending connection attempt
+            $connecting->then(function (ConnectionInterface $stream) {
+                $stream->close();
+            });
+            $connecting->cancel();
+        });
 
-        // start TCP/IP connection to SOCKS server and then
         // handle SOCKS protocol once connection is ready
         // resolve plain connection once SOCKS protocol is completed
-        return $this->connector->connect($socksUri)->then(
-            function (ConnectionInterface $stream) use ($that, $host, $port) {
-                return $that->handleConnectedSocks($stream, $host, $port);
+        $that = $this;
+        $connecting->then(
+            function (ConnectionInterface $stream) use ($that, $host, $port, $deferred) {
+                $that->handleConnectedSocks($stream, $host, $port, $deferred);
             },
-            function (Exception $e) {
-                throw new RuntimeException('Unable to connect to proxy (ECONNREFUSED)', defined('SOCKET_ECONNREFUSED') ? SOCKET_ECONNREFUSED : 111, $e);
+            function (Exception $e) use ($deferred) {
+                $deferred->reject($e = new RuntimeException(
+                    'Connection failed because connection to proxy failed (ECONNREFUSED)',
+                    defined('SOCKET_ECONNREFUSED') ? SOCKET_ECONNREFUSED : 111,
+                    $e
+                ));
+
+                // avoid garbage references by replacing all closures in call stack.
+                // what a lovely piece of code!
+                $r = new \ReflectionProperty('Exception', 'trace');
+                $r->setAccessible(true);
+                $trace = $r->getValue($e);
+                foreach ($trace as &$one) {
+                    foreach ($one['args'] as &$arg) {
+                        if ($arg instanceof \Closure) {
+                            $arg = 'Object(' . get_class($arg) . ')';
+                        }
+                    }
+                }
+                $r->setValue($e, $trace);
             }
         );
+
+        return $deferred->promise();
     }
 
     /**
@@ -178,14 +212,14 @@ function (Exception $e) {
      * @param ConnectionInterface $stream
      * @param string              $host
      * @param int                 $port
-     * @return Promise Promise<ConnectionInterface, Exception>
+     * @param Deferred            $deferred
+     * @return void
      * @internal
      */
-    public function handleConnectedSocks(ConnectionInterface $stream, $host, $port)
+    public function handleConnectedSocks(ConnectionInterface $stream, $host, $port, Deferred $d)
     {
-        $deferred = new Deferred(function ($_, $reject) {
-            $reject(new RuntimeException('Connection canceled while establishing SOCKS session (ECONNABORTED)', defined('SOCKET_ECONNABORTED') ? SOCKET_ECONNABORTED : 103));
-        });
+        $deferred = $d;
+        $d = null;
 
         $reader = new StreamReader();
         $stream->on('data', array($reader, 'write'));
@@ -203,32 +237,22 @@ public function handleConnectedSocks(ConnectionInterface $stream, $host, $port)
         } else {
             $promise = $this->handleSocks4($stream, $host, $port, $reader);
         }
-        $promise->then(function () use ($deferred, $stream) {
+
+        $promise->then(function () use ($deferred, $stream, $reader, $onError, $onClose) {
+            $stream->removeListener('data', array($reader, 'write'));
+            $stream->removeListener('error', $onError);
+            $stream->removeListener('close', $onClose);
+
             $deferred->resolve($stream);
-        }, function (Exception $error) use ($deferred) {
+        }, function (Exception $error) use ($deferred, $stream) {
             // pass custom RuntimeException through as-is, otherwise wrap in protocol error
             if (!$error instanceof RuntimeException) {
                 $error = new RuntimeException('Invalid response received from proxy (EBADMSG)', defined('SOCKET_EBADMSG') ? SOCKET_EBADMSG: 71, $error);
             }
 
             $deferred->reject($error);
+            $stream->close();
         });
-
-        return $deferred->promise()->then(
-            function (ConnectionInterface $stream) use ($reader, $onError, $onClose) {
-                $stream->removeListener('data', array($reader, 'write'));
-                $stream->removeListener('error', $onError);
-                $stream->removeListener('close', $onClose);
-
-                return $stream;
-            },
-            function ($error) use ($stream, $onClose) {
-                $stream->removeListener('close', $onClose);
-                $stream->close();
-
-                throw $error;
-            }
-        );
     }
 
     private function handleSocks4(ConnectionInterface $stream, $host, $port, StreamReader $reader)

tests/ClientTest.php

@@ -3,6 +3,7 @@
 use Clue\React\Socks\Client;
 use React\Promise\Promise;
 use Clue\React\Socks\Server;
+use React\Promise\Deferred;
 
 class ClientTest extends TestCase
 {
@@ -199,6 +200,22 @@ public function testCancelConnectionDuringSessionWillCloseStream()
         $promise->then(null, $this->expectCallableOnceWithExceptionCode(SOCKET_ECONNABORTED));
     }
 
+    public function testCancelConnectionDuringDeferredSessionWillCloseStream()
+    {
+        $stream = $this->getMockBuilder('React\Socket\Connection')->disableOriginalConstructor()->getMock();
+        $stream->expects($this->once())->method('close');
+
+        $deferred = new Deferred();
+
+        $this->connector->expects($this->once())->method('connect')->with('127.0.0.1:1080?hostname=google.com')->willReturn($deferred->promise());
+
+        $promise = $this->client->connect('google.com:80');
+        $deferred->resolve($stream);
+        $promise->cancel();
+
+        $promise->then(null, $this->expectCallableOnceWithExceptionCode(SOCKET_ECONNABORTED));
+    }
+
     public function testEmitConnectionCloseDuringSessionWillRejectConnection()
     {
         $stream = $this->getMockBuilder('React\Socket\Connection')->disableOriginalConstructor()->setMethods(array('write', 'close'))->getMock();
@@ -217,7 +234,6 @@ public function testEmitConnectionCloseDuringSessionWillRejectConnection()
     public function testEmitConnectionErrorDuringSessionWillRejectConnection()
     {
         $stream = $this->getMockBuilder('React\Socket\Connection')->disableOriginalConstructor()->setMethods(array('write', 'close'))->getMock();
-        $stream->expects($this->once())->method('close');
 
         $promise = \React\Promise\resolve($stream);
 
@@ -400,4 +416,62 @@ public function testEmitSocks5DataErrorMapsToExceptionCode($error, $expectedCode
 
         $promise->then(null, $this->expectCallableOnceWithExceptionCode($expectedCode));
     }
+
+    public function testConnectionErrorShouldNotCreateGarbageCycles()
+    {
+        if (class_exists('React\Promise\When')) {
+            $this->markTestSkipped('Not supported on legacy Promise v1 API');
+        }
+
+        $deferred = new Deferred();
+        $this->connector->expects($this->once())->method('connect')->willReturn($deferred->promise());
+
+        gc_collect_cycles();
+
+        $promise = $this->client->connect('google.com:80');
+        $deferred->reject(new RuntimeException());
+        unset($deferred, $promise);
+
+        $this->assertEquals(0, gc_collect_cycles());
+    }
+
+    public function testCancelConnectionDuringConnectionShouldNotCreateGarbageCycles()
+    {
+        if (class_exists('React\Promise\When')) {
+            $this->markTestSkipped('Not supported on legacy Promise v1 API');
+        }
+
+        $promise = new Promise(function () { }, function () {
+            throw new \RuntimeException();
+        });
+        $this->connector->expects($this->once())->method('connect')->willReturn($promise);
+
+        gc_collect_cycles();
+
+        $promise = $this->client->connect('google.com:80');
+        $promise->cancel();
+        unset($promise);
+
+        $this->assertEquals(0, gc_collect_cycles());
+    }
+
+    public function testCancelConnectionDuringSessionShouldNotCreateGarbageCycles()
+    {
+        if (class_exists('React\Promise\When')) {
+            $this->markTestSkipped('Not supported on legacy Promise v1 API');
+        }
+
+        $stream = $this->getMockBuilder('React\Socket\Connection')->disableOriginalConstructor()->setMethods(array('write'))->getMock();
+
+        $promise = new Promise(function ($resolve) use ($stream) { $resolve($stream); });
+        $this->connector->expects($this->once())->method('connect')->willReturn($promise);
+
+        gc_collect_cycles();
+
+        $promise = $this->client->connect('google.com:80');
+        $promise->cancel();
+        unset($promise);
+
+        $this->assertEquals(0, gc_collect_cycles());
+    }
 }