Learning The Hard Way

While I was working on developing a theme today I stumbled onto a really annoying thing that involves taxonomies and the new WordPress nav menu system. It's likely it would also happen with custom post types too but that I have not tested to know for sure or not. I have submitted a ticket #14181 for it, but it apparently was already reported here #13958.

So here's the deal...

I set up a custom taxonomy to add to the 'posts' post type. I then post a new sample post, which I created the hierarchy of terms for the custom tax I made, all of which I checked off to apply them to my sample post. That way there would be none that had an empty value.

I then created a new wp_nav_menu(), which I was planning to used as a drop menu for only displaying the terms of the custom tax I made. I set the menu up with the parent terms and each child term beneath them. The menu worked great, dropped down nicely, and was just fine and exactly what I was trying to do.

But then...

Naturally once I got it all working and doing what I wanted, I have to go and break that which is perfectly fine and completed. I decided that I needed to change the taxonomy's name, slug, query_var, etc. Basically I re-created the custom taxonomy using a different word for what it was called.

First let me explain why I not only did this, but I did it two times, and each time learned why it was a bad idea for me to do. The reason for changing the name of it the first time was because the original taxonomy I made was really just a generic thing, quickly done just to get it set up. The second time I re-named it was because I then needed to create a second custom taxonomy so I could use the two taxonomies as sort of the top level 'parent term' of the child terms. Only they were not terms, but more like separate containers that just needed to hold the child terms.

Update! - I jut awesomely did it for a 3rd time. I now know that it can happen even more likely to those less-savvy WordPress users. If you have a custom taxonomy and include terms of it in a nav menu, then you then decide to change your site theme to use a different one sort like how I just did, without removing the terms of the custom taxonomy first before changing themes. Yeah well, you're screwed then..

Taxonomy->Terms->Menu->Taxonomy Remake

This is a big No No...

Basically what I did was create something, add a whole bunch of things which use that something. Then took that whole bunch of things and added them to another thing which, is then dependent on that something as well. Then I destroyed that something and made a new thing, leaving those other things that were dependent on my somethings existence up the creek without a paddle. They were killed on impact.

In other words, when you add a bunch of terms for a custom taxonomy to a menu using the wp_nav, and then go and change, or re-create, re-structure, the taxonomy which the terms in the menu use. What is the result???

BOOM!!!

When I did this the first time I spent hours completely baffled as to what the hell could've happened, and searched and searched for some sort of answer. I read though some WordPress source files, and all kinds of possible explanations, only there was nothing helpful were to be found that involved my problem.

The Php error I was getting on my (now horribly broken page that was working perfectly before) was this:

Catchable fatal error: Object of class WP_Error could not be converted to string in C:\wamp\www\wp-includes\formatting.php on line 2829

On a side note: If you go and view line 2829 in this file, like I did, You will notice that the line the error occurred on is extremely unhelpful for figuring out what's broken, but it is humorous what the function this line falls on though.

So Yeah, This Bug Bites

Not only did I get the error above on my pages where the wp_nav_menu() function was called, in my dashboard on the menu management page this error was displayed, on a very broken and almost blank white page:

Catchable fatal error: Object of class WP_Error could not be converted to string in C:\wamp\www\new2wp\wp-includes\formatting.php on line 433

I am still not entirely sure about whether or not this is a bug, or some other type of thing I don't know about. After all, it was something that I only experience two times, and as far as I could find, those are the only two times it's happened. WordPress 3.0 is still extremely new, so I would imagine since I did it twice in one day, there are likely to be more people that it will happen to in the future if something isn't done to fix it.

I don't really even know what the hell is the problem, but it obviously has to do with taxonomies and the use of terms as links in a WP nav menu. There is some obvious reasons why something is bound to break when you have two things on a table and tie them together, only to kick out the legs that support them.

In my research on the possible reason this is able to break is there is most likely nothing in the wp_nav_menu code anywhere, where ever it would be needed, which does a check to see if a taxonomy exists, and if yes, are there terms which the menu has added.

I would imagine such a thing as this was done in the code. Since it is able to recognize custom taxonomies and post types, and allows for them to be used in the menus, there is definitely a check for taxonomy done somewhere at least. However, it may just be lacking that fallback function which provides some kind of emergency plan for when the shit hits the fan, and a once existing taxonomy or post type being used by the nav menu no long exists, and the world was about to end.

Why This Bug NEEDs Fixing

So this may not seem like too big a deal so far. However, I have found this bug/thing to be a bit more of a serious issue given the fact that once you have gone and changed your taxonomy and initiated the error, there is no going back.

What I Tried and Learned Is Not A Fix For It

• Remaking the taxonomy which was changed causing it to break. Even the previously used tax being made again had no effect in fixing the errors.
• several different queries
• rewriting the codes
• rebuilding each item from scratch again (taxonomy, terms, nav menu hierarchy of terms
• physically deleting each mention of the taxonomy, terms of it from within phpmyadmin
• among other things...

I did spend about 6 hours or so of the day trying to figure out what the hell I could've done to f*ck it all up. I didn't see the obvious reason it happened in the first place. As usual, it was my super-human doing that caused it all by removing an apparently more crucial thing that I had thought.

Forced To Reset WordPress To Defaults To Fix

I couldn't find any other way that didn't require such drastic actions as completely resetting the site. I wish I could've, too. I mean, I had do reset everything back up TWICE! That was like 20 minutes wasted each time just doing that whole process both times.

Has this happened to you yet

I'd like to know whether I'm the only awesomely sexy and lucky person who has had the joy of stressing out to the wonders this creates, breaking your site. Have you ever had anything in WordPress 3.0 break that was as major as the entire menu system? Post comments!!

UPDATE: I've broken my WAMP WordPress menu system for a third time. Meaning I now have to reset the whole thing AGAIN :(