5 files changed, 9 insertions, 5 deletions
diff --git a/phpBB/includes/cache/driver/file.php b/phpBB/includes/cache/driver/file.php
index 0d3b06f621..f64a9e3ea8 100644
--- a/phpBB/includes/cache/driver/file.php
+++ b/phpBB/includes/cache/driver/file.php
@@ -364,7 +364,7 @@ class phpbb_cache_driver_file extends phpbb_cache_driver_base
 	/**
 	* Save sql query
 	*/
-	function sql_save($query, &$query_result, $ttl)
+	function sql_save($query, $query_result, $ttl)
 	{
 		global $db;
 
@@ -385,6 +385,8 @@ class phpbb_cache_driver_file extends phpbb_cache_driver_base
 		{
 			$query_result = $query_id;
 		}
+
+		return $query_id;
 	}
 
 	/**
diff --git a/phpBB/includes/cache/driver/interface.php b/phpBB/includes/cache/driver/interface.php
index 313a2d4b31..847ba97262 100644
--- a/phpBB/includes/cache/driver/interface.php
+++ b/phpBB/includes/cache/driver/interface.php
@@ -75,7 +75,7 @@ interface phpbb_cache_driver_interface
 	/**
 	* Save sql query
 	*/
-	public function sql_save($query, &$query_result, $ttl);
+	public function sql_save($query, $query_result, $ttl);
 
 	/**
 	* Ceck if a given sql query exist in cache
diff --git a/phpBB/includes/cache/driver/memory.php b/phpBB/includes/cache/driver/memory.php
index e25c9229a1..e0771ab1d3 100644
--- a/phpBB/includes/cache/driver/memory.php
+++ b/phpBB/includes/cache/driver/memory.php
@@ -19,7 +19,7 @@ if (!defined('IN_PHPBB'))
 * ACM Abstract Memory Class
 * @package acm
 */
-class phpbb_cache_driver_memory extends phpbb_cache_driver_base
+abstract class phpbb_cache_driver_memory extends phpbb_cache_driver_base
 {
 	var $key_prefix;
 
@@ -280,7 +280,7 @@ class phpbb_cache_driver_memory extends phpbb_cache_driver_base
 	/**
 	* Save sql query
 	*/
-	function sql_save($query, &$query_result, $ttl)
+	function sql_save($query, $query_result, $ttl)
 	{
 		global $db;
 
@@ -335,6 +335,8 @@ class phpbb_cache_driver_memory extends phpbb_cache_driver_base
 		$this->_write('sql_' . $hash, $this->sql_rowset[$query_id], $ttl);
 
 		$query_result = $query_id;
+
+		return $query_id;
 	}
 
 	/**
diff --git a/phpBB/includes/cache/driver/null.php b/phpBB/includes/cache/driver/null.php
index c143803d0e..df2c6c026f 100644
--- a/phpBB/includes/cache/driver/null.php
+++ b/phpBB/includes/cache/driver/null.php
@@ -107,7 +107,7 @@ class phpbb_cache_driver_null extends phpbb_cache_driver_base
 	/**
 	* Save sql query
 	*/
-	function sql_save($query, &$query_result, $ttl)
+	function sql_save($query, $query_result, $ttl)
 	{
 	}
 
diff --git a/phpBB/includes/cache/driver/redis.php b/phpBB/includes/cache/driver/redis.php
index a768885962..a768885962 100755..100644
--- a/phpBB/includes/cache/driver/redis.php
+++ b/phpBB/includes/cache/driver/redis.php