It recently came to my attention that there's a patch for the recently released security patch, SUPEE-6788.
Magento Bug - Corrupted Config Cache
This includes a preface, symptoms of the issue, debugging, cause & explanation as well as the ability for replication & correcting the issue itself.
This patch isn't publicly listed anywhere because Magento don't do that for anything but security patches for some reason. I know the patch file says EE_1.13.1.0, but I tested it on community edition 1.9 and it applied fine.
Has anybody else run into the issue on Community edition? Symptom:
Your homepage fails to load the CSS, and a message is displayed saying There was no 404 CMS page configured or found.
I was able to reproduce the error using the proposed method as well as applied the fix and am no longer able to reproduce.
It may be worthwhile checking out your own instance of Magento with the script to reproduce the error & patch to avoid downtime.
Special thanks to Nexcess for pointing me to this solution.
An even bigger thanks to Luke Rodgers (#OfficialAuthor) for the weeks of work put into uncovering the problem & discovering the solution, you really saved me a lot of heartache & headaches.
EDIT:
Although the GitHub article covers everything in-depth, Luke does provide the 100-router-script.php as well as a phpunit test which should allow you to reproduce the issue.
The following symptoms would usually manifest when the website is experiencing high load, and very often after a cache flush was triggered. The symptoms persist until you flush the CONFIG cache.
Enterprise Edition
Your website produces nothing but Front controller reached 100 router match iterations reports. (Tested on Magento 1.12 and 1.13)
Community Edition
Your homepage fails to load the CSS, and a message is displayed saying There was no 404 CMS page configured or found.
I have not spent much time debugging the effects on the community edition, there are likely other symptoms. (Tested on Magento 1.9.1.0)
