For contribuited modules, I have taxonomy.access running.
I was getting the following error in watchdog on one of my each time cron.php would run either automatically, or manually via an anonymous user (like an automated crontab):
Invalid argument supplied for foreach() in /home/.ignacia/botpnetwork/temple.brotherhoodofthephoenix.org/spark/modules/taxonomy.module on line 1184.
The error would show up many times in a row within the same second each cron run.
However, If I was logged in to the Drupal site, and ran cron.php manually, the errors would not show up in Watchdog.
Alternativly, if I either unpublish any content that anonymous users aren't allowed to see (due to taxonmy.access) - or disable taxonomy.access entirely - I also don't get any errors in Watchdog.
Now, lets make matters weirder;
Search is saying:
0% of the site has been indexed. There are 10 items left to index.
Search settings:
10 items per cron run
Maximum word length: 3
NOTE: I have tried clicking reindex to flush the cache; changing the word length to 4; changing the word length from 3 to 4 then back to 3; and changing the items per cron from 10 up through to 500; - none make the site actually index during a cron
This stays the same no matter what fixes I try above (ie: unpubishing restricted content, turning off taxonomy.access, or running cron.php when I am logged into the drupal site).