Mage registry key "_singleton/awall/feed_extensions" already exists - magento

Question

when i laoding admin panel i got this error.
How can i solve this?
There has been an error processing your request
Mage registry key "_singleton/awall/feed_extensions" already exists
Trace:
#0 /var/www/magento_upgrade/app/Mage.php(222): Mage::throwException('Mage registry k...')
#1 /var/www/magento_upgrade/app/Mage.php(476): Mage::register('_singleton/awal...', false)
#2 /var/www/magento_upgrade/app/code/core/Mage/Core/Model/App.php(1316): Mage::getSingleton('awall/feed_exte...')
#3 /var/www/magento_upgrade/app/Mage.php(447): Mage_Core_Model_App->dispatchEvent('controller_acti...', Array)
#4 /var/www/magento_upgrade/app/code/core/Mage/Core/Controller/Varien/Action.php(528): Mage::dispatchEvent('controller_acti...', Array)
#5 /var/www/magento_upgrade/app/code/core/Mage/Adminhtml/Controller/Action.php(160): Mage_Core_Controller_Varien_Action->preDispatch()
#6 /var/www/magento_upgrade/app/code/core/Mage/Core/Controller/Varien/Action.php(408): Mage_Adminhtml_Controller_Action->preDispatch()
#7 /var/www/magento_upgrade/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(250): Mage_Core_Controller_Varien_Action->dispatch('index')
#8 /var/www/magento_upgrade/app/code/core/Mage/Core/Controller/Varien/Front.php(176): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#9 /var/www/magento_upgrade/app/code/core/Mage/Core/Model/App.php(354): Mage_Core_Controller_Varien_Front->dispatch()
#10 /var/www/magento_upgrade/app/Mage.php(683): Mage_Core_Model_App->run(Array)
#11 /var/www/magento_upgrade/index.php(87): Mage::run('', 'store')
#12 {main}

Answer 1

What Usman said is right but the mystery is how could this happen?
She must be using extension from AW, it has an observer in <controller_action_predispatch>
It will call class awall/feed_extensions, type Singleton
That's why it will create registry with name _singleton/awall/feed_extensions
To debug it, we can use php's debug backtrace.
Put this line in your Mage.php under public static function registry:
public static function registry($key)
{
$str = Varien_Debug::backtrace(true, false);
if(!empty($str)){
Mage::log($str);
}
if (isset(self::$_registry[$key])) {
return self::$_registry[$key];
}
return null;
}
Using this we can backtrace who call the registry (other than the observer) because in normal condition there should not any code that call the registry directly (_singleton/awall/feed_extensions) so it should have never been called more than once.
It will log the result in [MagentosRoot]/var/log/system.log
Make sure you have turn on your log settings, in admin panel:
System > Configuration > Developer > Log Settings > Enabled [Yes]
Because you can't open your admin panel right now, you need to change it directly from database
Use this query to see if you have turn on your log setting or not:
mysql> select * from core_config_data where path like 'dev/log/active';
+-----------+---------+----------+----------------+-------+
| config_id | scope | scope_id | path | value |
+-----------+---------+----------+----------------+-------+
| 244 | default | 0 | dev/log/active | 1 |
+-----------+---------+----------+----------------+-------+
1 row in set (0.00 sec)
value = 1 means you have turn it on.
If you haven't had that value in your database, just insert it:
insert into core_config_data (scope, scope_id, path, value) values ('default', 0, 'dev/log/active', 1);
If the value in database is 0, change it into 1.

Answer 2

This because you already registered the same key name _singleton/awall/feed_extensions. As you can see in Mage.php
public static function register($key, $value, $graceful = false)
{
if (isset(self::$_registry[$key])) {
if ($graceful) {
return;
}
self::throwException('Mage registry key "'.$key.'" already exists');
}
self::$_registry[$key] = $value;
}
So try to register using other name.

Answer 3

For me, it worked to simply delete all files related to AheadWorks ("AW" on them) and reinstalling, carefully this time, by putting each file on the corresponding folder.
Before refreshing the admin page, find Mage_Compiler.xml and make sure there's a line like <active>false</active>.
Daunting, a bit.
Otherwise, try this:
first go to app/etc/modules/aw_all.xml
change true to false
first go to app/etc/modules/aw_blog.xml
change true to false
then log in to admin you admin will work now.
then
go to system->tools->compilation
disable it.
now
first go to app/etc/modules/aw_all.xml
change false to true
go to app/etc/modules/aw_blog.xml
change false to true
and then check if it is working or not..

Answer 4

I'm late to this question but I had the same problem last night and hope this answer will help someone else (this error cost me a day). I'm using a Magento 1.9 application with a Mage World extension. On my local environment, I switched branches to work on something else but I kept getting the generic Magento error page. Looking at the var/log/system.xml, I saw this:
a:5:{i:0;s:70:"Mage registry key "_singleton/onestepcheckout/observer" already exists";i:1;s:1691:"#0 C:\Sites\myintent-shop\app\Mage.php(223): Mage::throwException('Mage registry k...')
#1 C:\Sites\myintent-shop\app\Mage.php(477): Mage::register('_singleton/ones...', false)
#2 C:\Sites\myintent-shop\app\code\core\Mage\Core\Model\App.php(1316): Mage::getSingleton('onestepcheckout...')
#3 C:\Sites\myintent-shop\app\Mage.php(448): Mage_Core_Model_App->dispatchEvent('controller_acti...', Array)
#4 C:\Sites\myintent-shop\app\code\core\Mage\Core\Controller\Varien\Action.php(339): Mage::dispatchEvent('controller_acti...', Array)
#5 C:\Sites\myintent-shop\app\code\core\Mage\Cms\Helper\Page.php(113): Mage_Core_Controller_Varien_Action->generateLayoutBlocks()
#6 C:\Sites\myintent-shop\app\code\core\Mage\Cms\Helper\Page.php(52): Mage_Cms_Helper_Page->_renderPage(Object(Mage_Cms_IndexController), 'home')
#7 C:\Sites\myintent-shop\app\code\core\Mage\Cms\controllers\IndexController.php(45): Mage_Cms_Helper_Page->renderPage(Object(Mage_Cms_IndexController), 'home')
#8 C:\Sites\myintent-shop\app\code\core\Mage\Core\Controller\Varien\Action.php(418): Mage_Cms_IndexController->indexAction()
#9 C:\Sites\myintent-shop\app\code\core\Mage\Core\Controller\Varien\Router\Standard.php(250): Mage_Core_Controller_Varien_Action->dispatch('index')
#10 C:\Sites\myintent-shop\app\code\core\Mage\Core\Controller\Varien\Front.php(172): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#11 C:\Sites\myintent-shop\app\code\core\Mage\Core\Model\App.php(354): Mage_Core_Controller_Varien_Front->dispatch()
#12 C:\Sites\myintent-shop\app\Mage.php(684): Mage_Core_Model_App->run(Array)
#13 C:\Sites\myintent-shop\index.php(87): Mage::run('', 'store')
#14 {main}";s:3:"url";s:1:"/";s:11:"script_name";s:10:"/index.php";s:4:"skin";s:7:"default";}
Turns out that I had to clear my cache directory. Easiest way to do this was to go to root -> var -> cache and delete all the "mage-*" folders within the "cache" folder (note: I kept the cdn.cache file).