What is the cause of "Front controller reached 100 router match iterations" error?

Question

As a Magento developer I have faced this problem tons of times, I know it is a misconfiguration problem when it occurs some modules are not loaded, neither their routers, causing the error. Most of the times it is solved with no action, other times you may flush the cache

I've read multiple posts about this, trying to debug placing some extra code in Magento core Front controller app/code/core/Mage/Core/Controller/Varien/Front.php, but at the end this only shows which module routers are missing, not why they are not being loaded. Every time it occurs I try to look which URLs are giving the error, but this is useless information, same as the code trace. It's always the same

Maybe it is caused by module conflicts? Maybe it is some cron task doing something wrong? Maybe some wrong code in older Magento versions? The thing is this problem does not occur since 1.7 version (or if it occurs then it is totally sporadic). I have found some code differences in the main flow, such as

Mage::register('application_params', $params);

In run() method of app/code/core/Mage/Core/Model/App.php, or the

$this->_shouldSkipProcessModulesUpdates()

check in _initModules() method...

I want to believe there should be someone who has definitively found the cause. Any tips?

Answer 1

It seems you were experiencing a Magento configuration bug.

There is an excellent write-up with solution here.

In that article the author was able to rectify the bug by overriding Mage_Core_Model_Config and forcing $_useCache = false when regenerating the config.

Answer 2

Check the Magento configuration settings Default No-route URL at

System > Configurations > Web > Default Pages

. It should be set the default value cms/index/noRoute. Check the particular store value as well whether it default value has been overwritten here. Magento can go into an infinite loop till it hits the 100 iterations limit if it is not set properly.

If you use Magerun, run this command.

magerun config:set cms/index/noRoute no-route

I have found the solution here, this is was the issue in my case. You can check the URL for other options.

https://merchantprotocol.com/506/solved-front-controller-reached-100-router-match-iterations/

Answer 3

If you're using Redis, simply restart Redis server