From 323d8cb19d60327ecfe4441214722c6bdc74bb2d Mon Sep 17 00:00:00 2001
From: spacedmonkey <spacedmonkey@git.wordpress.org>
Date: Mon, 18 Sep 2023 12:41:18 +0000
Subject: [PATCH] Plugins: Store result of call to array_keys, to save repeated
 calls in WP_Hook class.

In the `WP_Hook` class the function `array_keys` was called every time an array of hook priorities was needed. For sites with lots of filters or actions, this would result in thousands of calls to the `array_keys` function, which uses server resources. Instead of recomputing this array every time it is needed, only compute it when filters are added and removed, then store the result as a class property. Improve unit tests to ensure this behaviour is tested.

Props spacedmonkey, bor0, flixos90, hellofromTonya, mukesh27.
Fixes #58458.
Built from https://develop.svn.wordpress.org/trunk@56609


git-svn-id: http://core.svn.wordpress.org/trunk@56121 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/class-wp-hook.php | 25 +++++++++++++++++++++----
 wp-includes/version.php       |  2 +-
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/wp-includes/class-wp-hook.php b/wp-includes/class-wp-hook.php
index 9c1cac6d1c..d95691df6a 100644
--- a/wp-includes/class-wp-hook.php
+++ b/wp-includes/class-wp-hook.php
@@ -26,6 +26,14 @@ final class WP_Hook implements Iterator, ArrayAccess {
 	 */
 	public $callbacks = array();
 
+	/**
+	 * Priorities list.
+	 *
+	 * @since 6.4.0
+	 * @var array
+	 */
+	protected $priorities = array();
+
 	/**
 	 * The priority keys of actively running iterations of a hook.
 	 *
@@ -86,6 +94,8 @@ final class WP_Hook implements Iterator, ArrayAccess {
 			ksort( $this->callbacks, SORT_NUMERIC );
 		}
 
+		$this->priorities = array_keys( $this->callbacks );
+
 		if ( $this->nesting_level > 0 ) {
 			$this->resort_active_iterations( $priority, $priority_existed );
 		}
@@ -102,7 +112,7 @@ final class WP_Hook implements Iterator, ArrayAccess {
 	 *                                    filter was added. Default false.
 	 */
 	private function resort_active_iterations( $new_priority = false, $priority_existed = false ) {
-		$new_priorities = array_keys( $this->callbacks );
+		$new_priorities = $this->priorities;
 
 		// If there are no remaining hooks, clear out all running iterations.
 		if ( ! $new_priorities ) {
@@ -187,6 +197,8 @@ final class WP_Hook implements Iterator, ArrayAccess {
 			if ( ! $this->callbacks[ $priority ] ) {
 				unset( $this->callbacks[ $priority ] );
 
+				$this->priorities = array_keys( $this->callbacks );
+
 				if ( $this->nesting_level > 0 ) {
 					$this->resort_active_iterations();
 				}
@@ -262,9 +274,11 @@ final class WP_Hook implements Iterator, ArrayAccess {
 		}
 
 		if ( false === $priority ) {
-			$this->callbacks = array();
+			$this->callbacks  = array();
+			$this->priorities = array();
 		} elseif ( isset( $this->callbacks[ $priority ] ) ) {
 			unset( $this->callbacks[ $priority ] );
+			$this->priorities = array_keys( $this->callbacks );
 		}
 
 		if ( $this->nesting_level > 0 ) {
@@ -289,7 +303,7 @@ final class WP_Hook implements Iterator, ArrayAccess {
 
 		$nesting_level = $this->nesting_level++;
 
-		$this->iterations[ $nesting_level ] = array_keys( $this->callbacks );
+		$this->iterations[ $nesting_level ] = $this->priorities;
 
 		$num_args = count( $args );
 
@@ -348,7 +362,7 @@ final class WP_Hook implements Iterator, ArrayAccess {
 	 */
 	public function do_all_hook( &$args ) {
 		$nesting_level                      = $this->nesting_level++;
-		$this->iterations[ $nesting_level ] = array_keys( $this->callbacks );
+		$this->iterations[ $nesting_level ] = $this->priorities;
 
 		do {
 			$priority = current( $this->iterations[ $nesting_level ] );
@@ -481,6 +495,8 @@ final class WP_Hook implements Iterator, ArrayAccess {
 		} else {
 			$this->callbacks[ $offset ] = $value;
 		}
+
+		$this->priorities = array_keys( $this->callbacks );
 	}
 
 	/**
@@ -495,6 +511,7 @@ final class WP_Hook implements Iterator, ArrayAccess {
 	#[ReturnTypeWillChange]
 	public function offsetUnset( $offset ) {
 		unset( $this->callbacks[ $offset ] );
+		$this->priorities = array_keys( $this->callbacks );
 	}
 
 	/**
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 04edf6ca7b..52d3ab0262 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.4-alpha-56608';
+$wp_version = '6.4-alpha-56609';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.