Changeset 61176 for trunk/src/wp-includes/class-wp-scripts.php

Timestamp:

11/07/2025 06:11:24 AM (9 months ago)

Author:

westonruter

Message:

Script Loader: Guard against exponential recursion during calculation of loading strategy and fetchpriority.

This addresses a performance issue in the recursive WP_Scripts::get_highest_fetchpriority_with_dependents() and WP_Scripts::filter_eligible_strategies() methods for redundant processing of shared dependencies in complex dependency graphs. To fix this, a $stored_results param is introduced which is passed by reference; this variable contains a cache of the calculated results for all scripts handles, so that subsequent calls for the same handle can return the cached value instead of re-computing it.

Developed in ​https://github.com/WordPress/wordpress-develop/pull/10459

Follow-up to [60704], [60931], [56033].

Props ciobanucatalin, b1ink0, westonruter, mukesh27.
See #61734, #12009.
Fixes #64194.

File:

• trunk/src/wp-includes/class-wp-scripts.php (modified) (5 diffs)

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

@@ -998 +998 @@
          * @since 6.3.0
          *
-         * @param string              $handle              The script handle.
-         * @param string[]|null       $eligible_strategies Optional. The list of strategies to filter. Default null.
-         * @param array<string, true> $checked             Optional. An array of already checked script handles, used to avoid recursive loops.
+         * @param string                  $handle              The script handle.
+         * @param string[]|null           $eligible_strategies Optional. The list of strategies to filter. Default null.
+         * @param array<string, true>     $checked             Optional. An array of already checked script handles, used to avoid recursive loops.
+         * @param array<string, string[]> $stored_results      Optional. An array of already computed eligible loading strategies by handle, used to increase performance in large dependency lists.
          * @return string[] A list of eligible loading strategies that could be used.
          */
-        private function filter_eligible_strategies( $handle, $eligible_strategies = null, $checked = array() ) {
+        private function filter_eligible_strategies( $handle, $eligible_strategies = null, $checked = array(), array &$stored_results = array() ) {
+                if ( isset( $stored_results[ $handle ] ) ) {
+                        return $stored_results[ $handle ];
+                }
+
                 // If no strategies are being passed, all strategies are eligible.
                 if ( null === $eligible_strategies ) {
@@ -1054 +1059 @@
                         }
 
-                        $eligible_strategies = $this->filter_eligible_strategies( $dependent, $eligible_strategies, $checked );
-                }
-
+                        $eligible_strategies = $this->filter_eligible_strategies( $dependent, $eligible_strategies, $checked, $stored_results );
+                }
+                $stored_results[ $handle ] = $eligible_strategies;
                 return $eligible_strategies;
         }
@@ -1067 +1072 @@
          * @see WP_Script_Modules::get_highest_fetchpriority_with_dependents()
          *
-         * @param string              $handle  Script module ID.
-         * @param array<string, true> $checked Optional. An array of already checked script handles, used to avoid recursive loops.
+         * @param string                $handle         Script module ID.
+         * @param array<string, true>   $checked        Optional. An array of already checked script handles, used to avoid recursive loops.
+         * @param array<string, string> $stored_results Optional. An array of already computed max priority by handle, used to increase performance in large dependency lists.
          * @return string|null Highest fetch priority for the script and its dependents.
          */
-        private function get_highest_fetchpriority_with_dependents( string $handle, array $checked = array() ): ?string {
+        private function get_highest_fetchpriority_with_dependents( string $handle, array $checked = array(), array &$stored_results = array() ): ?string {
+                if ( isset( $stored_results[ $handle ] ) ) {
+                        return $stored_results[ $handle ];
+                }
+
                 // If there is a recursive dependency, return early.
                 if ( isset( $checked[ $handle ] ) ) {
@@ -1100 +1110 @@
                 if ( $highest_priority_index !== $high_priority_index ) {
                         foreach ( $this->get_dependents( $handle ) as $dependent_handle ) {
-                                $dependent_priority = $this->get_highest_fetchpriority_with_dependents( $dependent_handle, $checked );
+                                $dependent_priority = $this->get_highest_fetchpriority_with_dependents( $dependent_handle, $checked, $stored_results );
                                 if ( is_string( $dependent_priority ) ) {
                                         $highest_priority_index = max(
@@ -1112 +1122 @@
                         }
                 }
-
+                $stored_results[ $handle ] = $priorities[ $highest_priority_index ]; // @phpstan-ignore parameterByRef.type (We know the index is valid and that this will be a string.)
                 return $priorities[ $highest_priority_index ];
         }