It turns out there’s been a known problem since WordPress 2.1 was released two months ago. Some plugin hooks have changed, and plugins that used to only get called during post editing are also getting called during comment publishing. I grabbed an updated version of the plugin, and it seems okay now.

Oddly, most (but not all) tags survived unscathed during the two months running earlier 2.1 releases. It’s only since moving to 2.1.3 that it’s been consistent. Oh, well, at least it prompted me to find the fix.

Just replace this:

function add_tags_textinput() {
	global $postdata;
	$tags = get_post_meta($postdata->ID, 'tags', true);

with this:

function add_tags_textinput() {
	global $post_ID;
	$tags = get_post_meta($post_ID, 'tags', true);

The problem is that it will show existing tags, or let you add a new tag, but it will lose tags when you edit a post. It’s not able to retrieve the tags to fill in the form field, apparently because $postdata isn’t returning the ID it expects.

I’ve submitted the fix to wp-plugins.org, so if the author is keeping track of tickets there, the fix should show up in the next version of the plugin.

Update Jan. 3: The plugin author has released version 0.5 with a slightly different fix (plus a few other improvements), and it’s now compatible with WordPress 2.0.

One thing I haven’t figured out yet: since the list is separated by spaces, how do you specify a multi-word tag like “Internet Explorer”?

To be honest, this post only exists because I want to test it, and because there seems to be a tradition of “I just installed this neat new plugin” posts.

Update: multi+word doesn’t seem to work. (It was a guess based on URL encoding.) Technorati has picked this post up on “testing” but not “multi word.” Next attempt: double%20word (in case the first one was just slow)—but since I’m not sure whether Technorati will re-index this post until I add a new one, it may not be a useful test just yet.

Update 2: Two things: In the URL, WP encodes the % in %20. Figures. Also, that wouldn’t show up as a space in normal HTML. I am clearly sleep-deprived and must immediately begin a period of nocturnal inactivity for at least eight hours. Either that or down a glass or two of Dr. Pepper.

Having just glanced at the code, which I should have done in the first place, there does not appear to be any allowance for multi-word tags (it just uses the standard explode function). This leaves me with several choices:

1. Enable the option to use comma-separated keywords (losing the utility of the convenient form field)—and re-enable it every time I upgrade the plugin.
2. Contact the plug-in author and request the feature.
3. Hack the plug-in to enable it and submit the changes to the author.
4. Use a plug-in that takes another approach, like TechnoTag.

#3 sounds like my best bet, but I think I ought to sleep first.