The Delicious Brains site has a new post looking at an addition to the WordPress platform allowing you to hook into the core - the WP_Hook class. In the latest release of WordPress this system received a major overhaul and in this article they share what's been updated and what kind of impact it should have on your code.
The hooks system is a central pillar of WordPress and with the 4.7 release a major overhaul of how it works was merged. The Trac ticket that initially raised an issue with the hooks system was logged over 6 years ago. After a few attempts, the updates finally made it into the 4.7 release and the venerable hooks system was overhauled. In this post I want to go over some of the technical changes and decisions that went into the new WP_Hook class. I’ll also go over some of the more interesting aspects of WordPress core development and look into what it takes to overhaul a major feature in WordPress core.
The post starts out with what's changed related to the hooks handling, mostly that the functionality has moved out into a new "WP_Hook" class. This migrates it way from being handled right next to the plugin logic. He details some of the behind the scenes changes to the code and changes made to help improve performance. The post finishes out looking at the backwards compatibility of these changes and what it means for developers upgrading to this new WordPress version (hint: not much).