PHP:Notice: Only variable references should be returned by reference

    在我下载最新的codeigniter框架后，首次运行就出现了如下错误：

经过查资料知道，原来是在php5向后兼容不是很理想，当一个函数出现多个return语句时，就会出现这样的报错。
以下是框架原来的写法：
if ( ! function_exists('get_config'))
{
function &get_config($replace = array())
{
static $_config;


if (isset($_config))
{
return $_config[0];
}


// Is the config file in the environment folder?
if ( ! defined('ENVIRONMENT') OR ! file_exists($file_path = APPPATH.'config/'.ENVIRONMENT.'/config.php'))
{
$file_path = APPPATH.'config/config.php';
}


// Fetch the config file
if ( ! file_exists($file_path))
{
exit('The configuration file does not exist.');
}


require($file_path);


// Does the $config array exist in the file?
if ( ! isset($config) OR ! is_array($config))
{
exit('Your config file does not appear to be formatted correctly.');
}


// Are any values being dynamically replaced?
if (count($replace) > 0)
{
foreach ($replace as $key => $val)
{
if (isset($config[$key]))
{
$config[$key] = $val;
}
}
}


return $_config[0] =& $config;
}
}

通过增加一个$result中间变量，减少了return语句，终于恢复正常，代码如下：
if ( ! function_exists('get_config'))
{
function &get_config($replace = array())
{
static $_config;


if (isset($_config))
{
$result=$_config[0];
}


// Is the config file in the environment folder?
if ( ! defined('ENVIRONMENT') OR ! file_exists($file_path = APPPATH.'config/'.ENVIRONMENT.'/config.php'))
{
$file_path = APPPATH.'config/config.php';
}


// Fetch the config file
if ( ! file_exists($file_path))
{
exit('The configuration file does not exist.');
}


require($file_path);


// Does the $config array exist in the file?
if ( ! isset($config) OR ! is_array($config))
{
exit('Your config file does not appear to be formatted correctly.');
}


// Are any values being dynamically replaced?
if (count($replace) > 0)
{
foreach ($replace as $key => $val)
{
if (isset($config[$key]))
{
$config[$key] = $val;
}
}
}
if(!isset($result))
$result=& $config;
return $result;
}
}