I started a blog with some friends and I decided to use WordPress. I got everything setup – my web hosting provider (InnoHosting) provides a nice cPanel tool Installatron that did all of the significant work.
I started editing posts and noticed that I couldn't find any post revision history, even though that is a standard feature.
I installed the plugin Revision Control but the edit post page for any post shows the error message:
Error: WP_POST_REVISIONS is defined in your wp-config.php. Revision Control cannot operate.
I checked my wp-config.php file, but that constant was NOT defined in that file. Hmm. Maybe it's defined in some other file loaded by that file? I'm not fluent in PHP, so I don't know that that's even a reasonable hypothesis.
I downloaded the entire WordPress file tree from my site and tried to search those files looking for that constant. No results. I'm pretty sure the settings for the Google Desktop indexing plugin Larry's Any Text File Indexer don't include PHP files (because you can only specify the file extensions you want to be indexed once, when you first install the plugin). Hmm ...
Maybe SciTE can help me? Indeed! From the Search menu, pick Find in Files..., add the extension *.php, and pick the local folder where the WordPress files are located and presto! The culprit turned out to be the WordPress plugin Postie, which I installed to extend the standard functionality of the post-via-email feature. Fortunately, my writers don't really use that feature so I was able to deactivate Postie and then voila! Revision Control now works.
Hopefully this may help someone else also struggling to determine why the error message quoted above is lying to you!