Merge branch '3.0-stable' into develop

Resolved conflicts:
	system/core/CodeIgniter.php
	user_guide_src/source/changelog.rst
	user_guide_src/source/conf.py
	user_guide_src/source/installation/downloads.rst
	user_guide_src/source/installation/upgrading.rst

14 files changed, 190 insertions, 116 deletions

diff --git a/system/core/Loader.php b/system/core/Loader.php
index 62781a7bf..c742ae71a 100644
--- a/system/core/Loader.php
+++ b/system/core/Loader.php
@@ -936,6 +936,14 @@ class CI_Loader {
 		 */
 		if (is_array($_ci_vars))
 		{
+			foreach (array_keys($_ci_vars) as $key)
+			{
+				if (strncmp($key, '_ci_', 4) === 0)
+				{
+					unset($_ci_vars[$key]);
+				}
+			}
+
 			$this->_ci_cached_vars = array_merge($this->_ci_cached_vars, $_ci_vars);
 		}
 		extract($this->_ci_cached_vars);
diff --git a/system/core/Log.php b/system/core/Log.php
index 7c81d358b..1abdaa00e 100644
--- a/system/core/Log.php
+++ b/system/core/Log.php
@@ -191,6 +191,8 @@ class CI_Log {
 			return FALSE;
 		}
 
+		flock($fp, LOCK_EX);
+
 		// Instantiating DateTime with microseconds appended to initial date is needed for proper support of this format
 		if (strpos($this->_date_fmt, 'u') !== FALSE)
 		{
@@ -206,8 +208,6 @@ class CI_Log {
 
 		$message .= $this->_format_line($level, $date, $msg);
 
-		flock($fp, LOCK_EX);
-
 		for ($written = 0, $length = strlen($message); $written < $length; $written += $result)
 		{
 			if (($result = fwrite($fp, substr($message, $written))) === FALSE)
diff --git a/system/core/Security.php b/system/core/Security.php
index bad511dd3..d5305d1ca 100644
--- a/system/core/Security.php
+++ b/system/core/Security.php
@@ -762,7 +762,14 @@ class CI_Security {
 	 */
 	public function strip_image_tags($str)
 	{
-		return preg_replace(array('#<img[\s/]+.*?src\s*=\s*["\'](.+?)["\'].*?\>#', '#<img[\s/]+.*?src\s*=\s*(.+?).*?\>#'), '\\1', $str);
+		return preg_replace(
+			array(
+				'#<img[\s/]+.*?src\s*=\s*(["\'])([^\\1]+?)\\1.*?\>#i',
+				'#<img[\s/]+.*?src\s*=\s*?(([^\s"\'=<>`]+)).*?\>#i'
+			),
+			'\\2',
+			$str
+		);
 	}
 
 	// ----------------------------------------------------------------
diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index eb9620f16..c862d937d 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -531,38 +531,46 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 
 		is_bool($escape) OR $escape = $this->_protect_identifiers;
 
-		// Split multiple conditions
-		if ($escape === TRUE && preg_match_all('/\sAND\s|\sOR\s/i', $cond, $m, PREG_OFFSET_CAPTURE))
+		if ( ! $this->_has_operator($cond))
 		{
-			$newcond = '';
-			$m[0][] = array('', strlen($cond));
-
-			for ($i = 0, $c = count($m[0]), $s = 0;
-				$i < $c;
-				$s = $m[0][$i][1] + strlen($m[0][$i][0]), $i++)
-			{
-				$temp = substr($cond, $s, ($m[0][$i][1] - $s));
-				$newcond .= preg_match("/(\(*)?([\[\]\w\.'-]+)(\s*[^\"\[`'\w]+\s*)(.+)/i", $temp, $match)
-						? $match[1].$this->protect_identifiers($match[2]).$match[3].$this->protect_identifiers($match[4])
-						: $temp;
-
-				$newcond .= $m[0][$i][0];
-			}
-
-			$cond = ' ON '.$newcond;
-		}
-		// Split apart the condition and protect the identifiers
-		elseif ($escape === TRUE && preg_match("/(\(*)?([\[\]\w\.'-]+)(\s*[^\"\[`'\w]+\s*)(.+)/i", $cond, $match))
-		{
-			$cond = ' ON '.$match[1].$this->protect_identifiers($match[2]).$match[3].$this->protect_identifiers($match[4]);
+			$cond = ' USING ('.($escape ? $this->escape_identifiers($cond) : $cond).')';
 		}
-		elseif ( ! $this->_has_operator($cond))
+		elseif ($escape === FALSE)
 		{
-			$cond = ' USING ('.($escape ? $this->escape_identifiers($cond) : $cond).')';
+			$cond = ' ON '.$cond;
 		}
 		else
 		{
-			$cond = ' ON '.$cond;
+			// Split multiple conditions
+			if (preg_match_all('/\sAND\s|\sOR\s/i', $cond, $joints, PREG_OFFSET_CAPTURE))
+			{
+				$conditions = array();
+				$joints = $joints[0];
+				array_unshift($joints, array('', 0));
+
+				for ($i = count($joints) - 1, $pos = strlen($cond); $i >= 0; $i--)
+				{
+					$joints[$i][1] += strlen($joints[$i][0]); // offset
+					$conditions[$i] = substr($cond, $joints[$i][1], $pos - $joints[$i][1]);
+					$pos = $joints[$i][1] - strlen($joints[$i][0]);
+					$joints[$i] = $joints[$i][0];
+				}
+			}
+			else
+			{
+				$conditions = array($cond);
+				$joints = array('');
+			}
+
+			$cond = ' ON ';
+			for ($i = 0, $c = count($conditions); $i < $c; $i++)
+			{
+				$operator = $this->_get_operator($conditions[$i]);
+				$cond .= $joints[$i];
+				$cond .= preg_match("/(\(*)?([\[\]\w\.'-]+)".preg_quote($operator)."(.*)/i", $conditions[$i], $match)
+					? $match[1].$this->protect_identifiers($match[2]).$operator.$this->protect_identifiers($match[3])
+					: $conditions[$i];
+			}
 		}
 
 		// Do we want to escape the table name?
diff --git a/system/database/drivers/ibase/ibase_driver.php b/system/database/drivers/ibase/ibase_driver.php
index cbc1022ff..c1055c1e6 100644
--- a/system/database/drivers/ibase/ibase_driver.php
+++ b/system/database/drivers/ibase/ibase_driver.php
@@ -126,7 +126,7 @@ class CI_DB_ibase_driver extends CI_DB {
 	 */
 	protected function _execute($sql)
 	{
-		return ibase_query($this->conn_id, $sql);
+		return ibase_query(isset($this->_ibase_trans) ? $this->_ibase_trans : $this->conn_id, $sql);
 	}
 
 	// --------------------------------------------------------------------
diff --git a/system/libraries/Cache/drivers/Cache_apc.php b/system/libraries/Cache/drivers/Cache_apc.php
index dd18e7bc8..07ea8f474 100644
--- a/system/libraries/Cache/drivers/Cache_apc.php
+++ b/system/libraries/Cache/drivers/Cache_apc.php
@@ -49,6 +49,24 @@ defined('BASEPATH') OR exit('No direct script access allowed');
 class CI_Cache_apc extends CI_Driver {
 
 	/**
+	 * Class constructor
+	 *
+	 * Only present so that an error message is logged
+	 * if APC is not available.
+	 *
+	 * @return	void
+	 */
+	public function __construct()
+	{
+		if ( ! $this->is_supported())
+		{
+			log_message('error', 'Cache: Failed to initialize APC; extension not loaded/enabled?');
+		}
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
 	 * Get
 	 *
 	 * Look for a value in the cache. If it exists, return the data
@@ -198,13 +216,6 @@ class CI_Cache_apc extends CI_Driver {
 	 */
 	public function is_supported()
 	{
-		if ( ! extension_loaded('apc') OR ! ini_get('apc.enabled'))
-		{
-			log_message('debug', 'The APC PHP extension must be loaded to use APC Cache.');
-			return FALSE;
-		}
-
-		return TRUE;
+		return (extension_loaded('apc') && ini_get('apc.enabled'));
 	}
-
 }
diff --git a/system/libraries/Cache/drivers/Cache_memcached.php b/system/libraries/Cache/drivers/Cache_memcached.php
index c44958b97..7e67fc40f 100644
--- a/system/libraries/Cache/drivers/Cache_memcached.php
+++ b/system/libraries/Cache/drivers/Cache_memcached.php
@@ -107,6 +107,7 @@ class CI_Cache_memcached extends CI_Driver {
 		else
 		{
 			log_message('error', 'Cache: Failed to create Memcache(d) object; extension not loaded?');
+			return;
 		}
 
 		foreach ($this->_memcache_conf as $cache_server)
diff --git a/system/libraries/Cache/drivers/Cache_redis.php b/system/libraries/Cache/drivers/Cache_redis.php
index 81b49e2fc..e9194a499 100644
--- a/system/libraries/Cache/drivers/Cache_redis.php
+++ b/system/libraries/Cache/drivers/Cache_redis.php
@@ -91,6 +91,12 @@ class CI_Cache_redis extends CI_Driver
 	 */
 	public function __construct()
 	{
+		if ( ! $this->is_supported())
+		{
+			log_message('error', 'Cache: Failed to create Redis object; extension not loaded?');
+			return;
+		}
+
 		$config = array();
 		$CI =& get_instance();
 
diff --git a/system/libraries/Cache/drivers/Cache_wincache.php b/system/libraries/Cache/drivers/Cache_wincache.php
index f66080514..d6a0d4fb6 100644
--- a/system/libraries/Cache/drivers/Cache_wincache.php
+++ b/system/libraries/Cache/drivers/Cache_wincache.php
@@ -52,6 +52,24 @@ defined('BASEPATH') OR exit('No direct script access allowed');
 class CI_Cache_wincache extends CI_Driver {
 
 	/**
+	 * Class constructor
+	 *
+	 * Only present so that an error message is logged
+	 * if APC is not available.
+	 *
+	 * @return	void
+	 */
+	public function __construct()
+	{
+		if ( ! $this->is_supported())
+		{
+			log_message('error', 'Cache: Failed to initialize Wincache; extension not loaded/enabled?');
+		}
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
 	 * Get
 	 *
 	 * Look for a value in the cache. If it exists, return the data,
@@ -194,13 +212,6 @@ class CI_Cache_wincache extends CI_Driver {
 	 */
 	public function is_supported()
 	{
-		if ( ! extension_loaded('wincache') OR ! ini_get('wincache.ucenabled'))
-		{
-			log_message('debug', 'The Wincache PHP extension must be loaded to use Wincache Cache.');
-			return FALSE;
-		}
-
-		return TRUE;
+		return (extension_loaded('wincache') && ini_get('wincache.ucenabled'));
 	}
-
 }
diff --git a/system/libraries/Profiler.php b/system/libraries/Profiler.php
index cc7641436..cf455d3da 100644
--- a/system/libraries/Profiler.php
+++ b/system/libraries/Profiler.php
@@ -314,12 +314,14 @@ class CI_Profiler {
 
 			foreach ($_GET as $key => $val)
 			{
-				is_int($key) OR $key = "'".$key."'";
+				is_int($key) OR $key = "'".htmlspecialchars($key, ENT_QUOTES, config_item('charset'))."'";
+				$val = (is_array($val) OR is_object($val))
+					? '<pre>'.htmlspecialchars(print_r($val, TRUE), ENT_QUOTES, config_item('charset'))
+					: htmlspecialchars($val, ENT_QUOTES, config_item('charset'));
 
 				$output .= '<tr><td style="width:50%;color:#000;background-color:#ddd;padding:5px;">&#36;_GET['
 					.$key.']&nbsp;&nbsp; </td><td style="width:50%;padding:5px;color:#cd6e00;font-weight:normal;background-color:#ddd;">'
-					.((is_array($val) OR is_object($val)) ? '<pre>'.htmlspecialchars(stripslashes(print_r($val, TRUE))).'</pre>' : htmlspecialchars(stripslashes($val)))
-					."</td></tr>\n";
+					.$val."</td></tr>\n";
 			}
 
 			$output .= "</table>\n";
@@ -352,36 +354,26 @@ class CI_Profiler {
 
 			foreach ($_POST as $key => $val)
 			{
-				is_int($key) OR $key = "'".$key."'";
+				is_int($key) OR $key = "'".htmlspecialchars($key, ENT_QUOTES, config_item('charset'))."'";
+				$val = (is_array($val) OR is_object($val))
+					? '<pre>'.htmlspecialchars(print_r($val, TRUE), ENT_QUOTES, config_item('charset'))
+					: htmlspecialchars($val, ENT_QUOTES, config_item('charset'));
 
 				$output .= '<tr><td style="width:50%;padding:5px;color:#000;background-color:#ddd;">&#36;_POST['
-					.$key.']&nbsp;&nbsp; </td><td style="width:50%;padding:5px;color:#009900;font-weight:normal;background-color:#ddd;">';
-
-				if (is_array($val) OR is_object($val))
-				{
-					$output .= '<pre>'.htmlspecialchars(stripslashes(print_r($val, TRUE))).'</pre>';
-				}
-				else
-				{
-					$output .= htmlspecialchars(stripslashes($val));
-				}
-
-				$output .= "</td></tr>\n";
+					.$key.']&nbsp;&nbsp; </td><td style="width:50%;padding:5px;color:#009900;font-weight:normal;background-color:#ddd;">'
+					.$val."</td></tr>\n";
 			}
 
 			foreach ($_FILES as $key => $val)
 			{
-				is_int($key) OR $key = "'".$key."'";
+				is_int($key) OR $key = "'".htmlspecialchars($key, ENT_QUOTES, config_item('charset'))."'";
+				$val = (is_array($val) OR is_object($val))
+					? '<pre>'.htmlspecialchars(print_r($val, TRUE), ENT_QUOTES, config_item('charset'))
+					: htmlspecialchars($val, ENT_QUOTES, config_item('charset'));
 
 				$output .= '<tr><td style="width:50%;padding:5px;color:#000;background-color:#ddd;">&#36;_FILES['
-					.$key.']&nbsp;&nbsp; </td><td style="width:50%;padding:5px;color:#009900;font-weight:normal;background-color:#ddd;">';
-
-				if (is_array($val) OR is_object($val))
-				{
-					$output .= '<pre>'.htmlspecialchars(stripslashes(print_r($val, TRUE))).'</pre>';
-				}
-
-				$output .= "</td></tr>\n";
+					.$key.']&nbsp;&nbsp; </td><td style="width:50%;padding:5px;color:#009900;font-weight:normal;background-color:#ddd;">'
+					.$val."</td></tr>\n";
 			}
 
 			$output .= "</table>\n";
@@ -465,7 +457,7 @@ class CI_Profiler {
 
 		foreach (array('HTTP_ACCEPT', 'HTTP_USER_AGENT', 'HTTP_CONNECTION', 'SERVER_PORT', 'SERVER_NAME', 'REMOTE_ADDR', 'SERVER_SOFTWARE', 'HTTP_ACCEPT_LANGUAGE', 'SCRIPT_NAME', 'REQUEST_METHOD',' HTTP_HOST', 'REMOTE_HOST', 'CONTENT_TYPE', 'SERVER_PROTOCOL', 'QUERY_STRING', 'HTTP_ACCEPT_ENCODING', 'HTTP_X_FORWARDED_FOR', 'HTTP_DNT') as $header)
 		{
-			$val = isset($_SERVER[$header]) ? $_SERVER[$header] : '';
+			$val = isset($_SERVER[$header]) ? htmlspecialchars($_SERVER[$header], ENT_QUOTES, config_item('charset')) : '';
 			$output .= '<tr><td style="vertical-align:top;width:50%;padding:5px;color:#900;background-color:#ddd;">'
 				.$header.'&nbsp;&nbsp;</td><td style="width:50%;padding:5px;color:#000;background-color:#ddd;">'.$val."</td></tr>\n";
 		}
diff --git a/system/libraries/Session/Session_driver.php b/system/libraries/Session/Session_driver.php
index 98fc897e3..55ddb25e0 100644
--- a/system/libraries/Session/Session_driver.php
+++ b/system/libraries/Session/Session_driver.php
@@ -168,4 +168,24 @@ abstract class CI_Session_driver implements SessionHandlerInterface {
 		return TRUE;
 	}
 
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Fail
+	 *
+	 * Drivers other than the 'files' one don't (need to) use the
+	 * session.save_path INI setting, but that leads to confusing
+	 * error messages emitted by PHP when open() or write() fail,
+	 * as the message contains session.save_path ...
+	 * To work around the problem, the drivers will call this method
+	 * so that the INI is set just in time for the error message to
+	 * be properly generated.
+	 *
+	 * @return	mixed
+	 */
+	protected function _fail()
+	{
+		ini_set('session.save_path', config_item('sess_save_path'));
+		return $this->_failure;
+	}
 }
diff --git a/system/libraries/Session/drivers/Session_database_driver.php b/system/libraries/Session/drivers/Session_database_driver.php
index 3ba9d3d36..317bd7d4d 100644
--- a/system/libraries/Session/drivers/Session_database_driver.php
+++ b/system/libraries/Session/drivers/Session_database_driver.php
@@ -127,7 +127,7 @@ class CI_Session_database_driver extends CI_Session_driver implements SessionHan
 	{
 		if (empty($this->_db->conn_id) && ! $this->_db->db_connect())
 		{
-			return $this->_failure;
+			return $this->_fail();
 		}
 
 		return $this->_success;
@@ -163,7 +163,7 @@ class CI_Session_database_driver extends CI_Session_driver implements SessionHan
 				$this->_db->where('ip_address', $_SERVER['REMOTE_ADDR']);
 			}
 
-			if (($result = $this->_db->get()->row()) === NULL)
+			if ( ! ($result = $this->_db->get()) OR ($result = $result->row()) === NULL)
 			{
 				// PHP7 will reuse the same SessionHandler object after
 				// ID regeneration, so we need to explicitly set this to
@@ -210,7 +210,7 @@ class CI_Session_database_driver extends CI_Session_driver implements SessionHan
 		{
 			if ( ! $this->_release_lock() OR ! $this->_get_lock($session_id))
 			{
-				return $this->_failure;
+				return $this->_fail();
 			}
 
 			$this->_row_exists = FALSE;
@@ -218,7 +218,7 @@ class CI_Session_database_driver extends CI_Session_driver implements SessionHan
 		}
 		elseif ($this->_lock === FALSE)
 		{
-			return $this->_failure;
+			return $this->_fail();
 		}
 
 		if ($this->_row_exists === FALSE)
@@ -237,7 +237,7 @@ class CI_Session_database_driver extends CI_Session_driver implements SessionHan
 				return $this->_success;
 			}
 
-			return $this->_failure;
+			return $this->_fail();
 		}
 
 		$this->_db->where('id', $session_id);
@@ -260,7 +260,7 @@ class CI_Session_database_driver extends CI_Session_driver implements SessionHan
 			return $this->_success;
 		}
 
-		return $this->_failure;
+		return $this->_fail();
 	}
 
 	// ------------------------------------------------------------------------
@@ -275,7 +275,7 @@ class CI_Session_database_driver extends CI_Session_driver implements SessionHan
 	public function close()
 	{
 		return ($this->_lock && ! $this->_release_lock())
-			? $this->_failure
+			? $this->_fail()
 			: $this->_success;
 	}
 
@@ -304,7 +304,7 @@ class CI_Session_database_driver extends CI_Session_driver implements SessionHan
 
 			if ( ! $this->_db->delete($this->_config['save_path']))
 			{
-				return $this->_failure;
+				return $this->_fail();
 			}
 		}
 
@@ -314,7 +314,7 @@ class CI_Session_database_driver extends CI_Session_driver implements SessionHan
 			return $this->_success;
 		}
 
-		return $this->_failure;
+		return $this->_fail();
 	}
 
 	// ------------------------------------------------------------------------
@@ -334,7 +334,7 @@ class CI_Session_database_driver extends CI_Session_driver implements SessionHan
 
 		return ($this->_db->delete($this->_config['save_path'], 'timestamp < '.(time() - $maxlifetime)))
 			? $this->_success
-			: $this->_failure;
+			: $this->_fail();
 	}
 
 	// ------------------------------------------------------------------------
@@ -414,5 +414,4 @@ class CI_Session_database_driver extends CI_Session_driver implements SessionHan
 
 		return parent::_release_lock();
 	}
-
 }
\ No newline at end of file
diff --git a/system/libraries/Session/drivers/Session_memcached_driver.php b/system/libraries/Session/drivers/Session_memcached_driver.php
index d017dfb2f..88eb4b3a6 100644
--- a/system/libraries/Session/drivers/Session_memcached_driver.php
+++ b/system/libraries/Session/drivers/Session_memcached_driver.php
@@ -117,7 +117,7 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa
 		{
 			$this->_memcached = NULL;
 			log_message('error', 'Session: Invalid Memcached save path format: '.$this->_config['save_path']);
-			return $this->_failure;
+			return $this->_fail();
 		}
 
 		foreach ($matches as $match)
@@ -142,7 +142,7 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa
 		if (empty($server_list))
 		{
 			log_message('error', 'Session: Memcached server pool is empty.');
-			return $this->_failure;
+			return $this->_fail();
 		}
 
 		return $this->_success;
@@ -170,7 +170,7 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa
 			return $session_data;
 		}
 
-		return $this->_failure;
+		return $this->_fail();
 	}
 
 	// ------------------------------------------------------------------------
@@ -188,14 +188,14 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa
 	{
 		if ( ! isset($this->_memcached))
 		{
-			return $this->_failure;
+			return $this->_fail();
 		}
 		// Was the ID regenerated?
 		elseif ($session_id !== $this->_session_id)
 		{
 			if ( ! $this->_release_lock() OR ! $this->_get_lock($session_id))
 			{
-				return $this->_failure;
+				return $this->_fail();
 			}
 
 			$this->_fingerprint = md5('');
@@ -204,24 +204,33 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa
 
 		if (isset($this->_lock_key))
 		{
+			$key = $this->_key_prefix.$session_id;
+
 			$this->_memcached->replace($this->_lock_key, time(), 300);
 			if ($this->_fingerprint !== ($fingerprint = md5($session_data)))
 			{
-				if ($this->_memcached->set($this->_key_prefix.$session_id, $session_data, $this->_config['expiration']))
+				if (
+					$this->_memcached->replace($key, $session_data, $this->_config['expiration'])
+					OR ($this->_memcached->getResultCode() === Memcached::RES_NOTFOUND && $this->_memcached->set($key, $session_data, $this->_config['expiration']))
+				)
 				{
 					$this->_fingerprint = $fingerprint;
 					return $this->_success;
 				}
 
-				return $this->_failure;
+				return $this->_fail();
 			}
 
-			return $this->_memcached->touch($this->_key_prefix.$session_id, $this->_config['expiration'])
-				? $this->_success
-				: $this->_failure;
+			if (
+				$this->_memcached->touch($key, $this->_config['expiration'])
+				OR ($this->_memcached->getResultCode() === Memcached::RES_NOTFOUND && $this->_memcached->set($key, $session_data, $this->_config['expiration']))
+			)
+			{
+				return $this->_success;
+			}
 		}
 
-		return $this->_failure;
+		return $this->_fail();
 	}
 
 	// ------------------------------------------------------------------------
@@ -237,17 +246,17 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa
 	{
 		if (isset($this->_memcached))
 		{
-			isset($this->_lock_key) && $this->_memcached->delete($this->_lock_key);
+			$this->_release_lock();
 			if ( ! $this->_memcached->quit())
 			{
-				return $this->_failure;
+				return $this->_fail();
 			}
 
 			$this->_memcached = NULL;
 			return $this->_success;
 		}
 
-		return $this->_failure;
+		return $this->_fail();
 	}
 
 	// ------------------------------------------------------------------------
@@ -269,7 +278,7 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa
 			return $this->_success;
 		}
 
-		return $this->_failure;
+		return $this->_fail();
 	}
 
 	// ------------------------------------------------------------------------
@@ -305,9 +314,12 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa
 		// correct session ID.
 		if ($this->_lock_key === $this->_key_prefix.$session_id.':lock')
 		{
-			return ($this->_memcached->replace($this->_lock_key, time(), 300))
-				? $this->_success
-				: $this->_failure;
+			if ( ! $this->_memcached->replace($this->_lock_key, time(), 300))
+			{
+				return ($this->_memcached->getResultCode() === Memcached::RES_NOTFOUND)
+					? $this->_memcached->set($this->_lock_key, time(), 300)
+					: FALSE;
+			}
 		}
 
 		// 30 attempts to obtain a lock, in case another request already has it
@@ -324,7 +336,7 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa
 			if ( ! $this->_memcached->set($lock_key, time(), 300))
 			{
 				log_message('error', 'Session: Error while trying to obtain lock for '.$this->_key_prefix.$session_id);
-				return $this->_failure;
+				return FALSE;
 			}
 
 			$this->_lock_key = $lock_key;
@@ -335,11 +347,11 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa
 		if ($attempt === 30)
 		{
 			log_message('error', 'Session: Unable to obtain lock for '.$this->_key_prefix.$session_id.' after 30 attempts, aborting.');
-			return $this->_failure;
+			return FALSE;
 		}
 
 		$this->_lock = TRUE;
-		return $this->_success;
+		return TRUE;
 	}
 
 	// ------------------------------------------------------------------------
@@ -367,5 +379,4 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa
 
 		return TRUE;
 	}
-
-}
+}
\ No newline at end of file
diff --git a/system/libraries/Session/drivers/Session_redis_driver.php b/system/libraries/Session/drivers/Session_redis_driver.php
index c0c20a7ca..ad14cbfdc 100644
--- a/system/libraries/Session/drivers/Session_redis_driver.php
+++ b/system/libraries/Session/drivers/Session_redis_driver.php
@@ -143,7 +143,7 @@ class CI_Session_redis_driver extends CI_Session_driver implements SessionHandle
 	{
 		if (empty($this->_config['save_path']))
 		{
-			return $this->_failure;
+			return $this->_fail();
 		}
 
 		$redis = new Redis();
@@ -176,7 +176,7 @@ class CI_Session_redis_driver extends CI_Session_driver implements SessionHandle
 			log_message('error', 'Session: Unable to connect to Redis with the configured settings.');
 		}
 
-		return $this->_failure;
+		return $this->_fail();
 	}
 
 	// ------------------------------------------------------------------------
@@ -206,7 +206,7 @@ class CI_Session_redis_driver extends CI_Session_driver implements SessionHandle
 			return $session_data;
 		}
 
-		return $this->_failure;
+		return $this->_fail();
 	}
 
 	// ------------------------------------------------------------------------
@@ -224,14 +224,14 @@ class CI_Session_redis_driver extends CI_Session_driver implements SessionHandle
 	{
 		if ( ! isset($this->_redis))
 		{
-			return $this->_failure;
+			return $this->_fail();
 		}
 		// Was the ID regenerated?
 		elseif ($session_id !== $this->_session_id)
 		{
 			if ( ! $this->_release_lock() OR ! $this->_get_lock($session_id))
 			{
-				return $this->_failure;
+				return $this->_fail();
 			}
 
 			$this->_key_exists = FALSE;
@@ -250,15 +250,15 @@ class CI_Session_redis_driver extends CI_Session_driver implements SessionHandle
 					return $this->_success;
 				}
 
-				return $this->_failure;
+				return $this->_fail();
 			}
 
 			return ($this->_redis->setTimeout($this->_key_prefix.$session_id, $this->_config['expiration']))
 				? $this->_success
-				: $this->_failure;
+				: $this->_fail();
 		}
 
-		return $this->_failure;
+		return $this->_fail();
 	}
 
 	// ------------------------------------------------------------------------
@@ -280,7 +280,7 @@ class CI_Session_redis_driver extends CI_Session_driver implements SessionHandle
 					$this->_release_lock();
 					if ($this->_redis->close() === $this->_failure)
 					{
-						return $this->_failure;
+						return $this->_fail();
 					}
 				}
 			}
@@ -319,7 +319,7 @@ class CI_Session_redis_driver extends CI_Session_driver implements SessionHandle
 			return $this->_success;
 		}
 
-		return $this->_failure;
+		return $this->_fail();
 	}
 
 	// ------------------------------------------------------------------------