Changeset 61008 for trunk/src/wp-includes/default-filters.php

Timestamp:

10/21/2025 05:59:38 AM (12 months ago)

Author:

westonruter

Message:

Script Loader: Load block styles on demand in classic themes via the template enhancement output buffer.

• This applies in classic themes when a site has not opted out of the template enhancement buffer by filtering wp_should_output_buffer_template_for_enhancement off.
• Both should_load_separate_core_block_assets and should_load_block_assets_on_demand are filtered on, as otherwise they are only enabled by default in block themes.
• Any style enqueued after wp_head and printed via print_late_styles() will get hoisted up to be inserted right after the wp-block-library inline style in the HEAD.
• The result is a >10% benchmarked improvement in LCP for core classic themes due to a ~100KB reduction in the amount of CSS unconditionally being served with every page load.

Developed in ​https://github.com/WordPress/wordpress-develop/pull/10288

Follow-up to [60936].

Props sjapaget, westonruter, peterwilsoncc, dmsnell, mindctrl.
See #43258.
Fixes #64099.

File:

• trunk/src/wp-includes/default-filters.php (modified) (1 diff)

trunk/src/wp-includes/default-filters.php

@@ -596 +596 @@
 add_action( 'enqueue_block_assets', 'wp_enqueue_registered_block_scripts_and_styles' );
 add_action( 'enqueue_block_assets', 'enqueue_block_styles_assets', 30 );
+add_action( 'init', 'wp_load_classic_theme_block_styles_on_demand', 8 ); // Must happen before register_core_block_style_handles() at priority 9.
 /*
  * `wp_enqueue_registered_block_scripts_and_styles` is bound to both