When I came to it the other week the site was in desparate need of updating, my Drupal versions had lagged behind far more than I'd care to admit to and this meant upgrading was no easy task. After making my way up through the various versions and sorting out the little niggles as I went I believed I had achieved the impossible and had a fairly stable site on my hands. That was until I broke it last night. I didn't think I'd done anything too drastic, and, as it turned out in the end, I hadn't, but it took a whole evening and morning to root out the problem (or perhaps I am just incredibly slow). I thought I'd write this post as a reminder to myself, don't feel you have to read it, it's incredibly dull!

I came up with the bright idea yesterday afternoon to tag my content. I like tags, perhaps more than I should, they appeal to me somehow, they're both organised and messy, my kind of structure. I tracked down a nice little tagging module and within ten minutes had it all installed and working nicely. The only slight problem being that the tags only showed up when I logged in... not really much use! A quick trawl around drupal.org and I hit upon the suggestion to rebuild my access permissions. Ok, ignoring all the "this can't be undone" signs I went about rebuilding. It failed

Now I had a greater problem on my hands, anonymous users could only view blog entries from 2006 and back and some of my other content had vanished. Mucho head scratching, taxonomy access was set correctly (particularly after I tweaked my css so I could see the 'list' checkbox which was hiding off of the page). There were no access permissions I could see that could be wrong. The site cache was flushed and turned off whilst I sorted the problem. I tried downloading the db to my local server and increasing php's memory allocation. I tried turning off modules, including taxonomy access (which allowed anonymous users to then see all content... so it was there) and then turning things on bit by bit. I tried manually flushing the node_access table. It definitely seemed to be the rebuilding permissions bit, which was still failing.

I finally bit the bullet and decided to have a look at the node_access table to try and figure out how it worked and what was going wrong. I got lucky, the first row I picked led me straight to the culprate.

And so, if by chance I see this problem again, or perhaps some poor soul has been inflicted with the same, the lesson to be learnt and the fix I found... I had a bunch of nodes in my node_revisions table, images from galleries I thought I'd deleted during the mass upgrade, nodes that no longer had a home or place on the site. Taxonomy_access doesn't like orphaned content it seems, a quick delete and all it's back to normal.

Simple