Fix segfault when channel zval type != IS_OBJECT

php_amqp.h

@@ -233,8 +233,7 @@ struct _amqp_connection_object {
 #endif
 
 
-#define PHP_AMQP_GET_CHANNEL_RESOURCE(obj) (PHP_AMQP_GET_CHANNEL(obj))->channel_resource
-
+#define PHP_AMQP_GET_CHANNEL_RESOURCE(obj) (IS_OBJECT == Z_TYPE_P(obj) ? (PHP_AMQP_GET_CHANNEL(obj))->channel_resource : NULL)
 
 #define PHP_AMQP_VERIFY_CONNECTION_ERROR(error, reason) \
 		char verify_connection_error_tmp[255]; \

tests/amqpexchange_declare_with_stalled_reference.phpt

@@ -0,0 +1,40 @@
+--TEST--
+AMQPExchange - declare with stalled reference
+--SKIPIF--
+<?php if (!extension_loaded("amqp")) print "skip"; ?>
+--FILE--
+<?php
+class ConnectionMock extends  AMQPConnection {
+    public function __construct(array $credentials = array())
+    {
+    }
+}
+
+class ChannelMock extends AMQPChannel {
+    public function __construct(AMQPConnection $amqp_connection)
+    {
+    }
+}
+
+class ExchangeMock extends \AMQPExchange
+{
+    public function __construct(AMQPChannel $amqp_channel)
+    {
+    }
+}
+
+$cnn = new ConnectionMock();
+$ch = new ChannelMock($cnn);
+
+$e = new ExchangeMock($ch);
+
+
+try {
+    $e->declareExchange();
+} catch (\Exception $e) {
+    echo get_class($e), ': ', $e->getMessage(), PHP_EOL;
+}
+
+?>
+--EXPECT--
+AMQPChannelException: Could not declare exchange. Stale reference to the channel object.

tests/amqpqueue_declare_with_stalled_reference.phpt

@@ -0,0 +1,40 @@
+--TEST--
+AMQPQueue - declare with stalled reference
+--SKIPIF--
+<?php if (!extension_loaded("amqp")) print "skip"; ?>
+--FILE--
+<?php
+class ConnectionMock extends  AMQPConnection {
+    public function __construct(array $credentials = array())
+    {
+    }
+}
+
+class ChannelMock extends AMQPChannel {
+    public function __construct(AMQPConnection $amqp_connection)
+    {
+    }
+}
+
+class QueueMock extends \AMQPQueue
+{
+    public function __construct(AMQPChannel $amqp_channel)
+    {
+    }
+}
+
+$cnn = new ConnectionMock();
+$ch = new ChannelMock($cnn);
+
+$e = new QueueMock($ch);
+
+
+try {
+    $e->declareQueue();
+} catch (\Exception $e) {
+    echo get_class($e), ': ', $e->getMessage(), PHP_EOL;
+}
+
+?>
+--EXPECT--
+AMQPChannelException: Could not declare queue. Stale reference to the channel object.