mike.banavige

I bumped into this myself on version 1.4.6.
It appears to be triggered by posting to a php file in the root directory.
I noticed these files triggering the delete of my cached root page (only on a POST, not on a GET):
wp-login.php
xmlrpc.php
wp-cron.php

And if you think you’re the only one hitting you login page, better double check your server logs as you may have a bot hitting that page behind your back trying to break in… 😉

In the plugin file wp-cache-phase2.php, the method that’s doing the delete is: function wp_cache_ob_callback

the code block down on line 317 is being entered:

if ( is_array( $do_rebuild_list ) && false == empty( $do_rebuild_list ) ) {

i temporarily updated my code to skip that rebuild logic when the current page is one that’s flagged to not cache. so my line 317 became:

if ( is_array( $do_rebuild_list ) && false == empty( $do_rebuild_list ) && wp_cache_is_rejected($_SERVER['REQUEST_URI']) == false ) {

Don’t yet know if this will have any negative side-effects (such as stranding old cache page copies), but I’m preloading the cache regularly so those cache page copies will still update with each preload run.