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

4 files changed, 74 insertions, 44 deletions

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();
 	}
 
 	// ------------------------------------------------------------------------