Changeset 56933

Timestamp:

10/13/2023 06:44:12 PM (10 months ago)

Author:

westonruter

Message:

Script Loader: Move delayed head script to footer when there is a blocking footer dependent.

This prevents a performance regression when a blocking script is enqueued in the footer which depends on a delayed script in the head (with async or defer). In order to preserve the execution order, a delayed dependency must fall back to blocking when there is a blocking dependent. But since it was originally delayed (and thus executes similarly to a footer script), it does not need to be in the head and can be moved to the footer. This prevents blocking the critical rendering path.

Props adamsilverstein, westonruter, flixos90.
Fixes #59599.
See #12009.

Location:

trunk

Files:

• src/wp-includes/class-wp-scripts.php (modified) (2 diffs)
• tests/phpunit/tests/dependencies/scripts.php (modified) (1 diff)

trunk/src/wp-includes/class-wp-scripts.php

@@ -233 +233 @@
 
     /**
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      * Processes a script dependency.
      *
@@ -280 +299 @@
         if ( ! $this->is_delayed_strategy( $intended_strategy ) ) {
             $intended_strategy = '';
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         }
 

trunk/tests/phpunit/tests/dependencies/scripts.php

@@ -3066 +3066 @@
         add_theme_support( 'html5', array( 'script' ) );
     }
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 }