From 8d65dc9eed20baa0b2b718426e6196699cf14b87 Mon Sep 17 00:00:00 2001
From: Joe McGill <joemcgill@git.wordpress.org>
Date: Wed, 6 Sep 2023 18:06:47 +0000
Subject: [PATCH] Themes: Avoid stale caches for core block styles.

This fixes an issue introduced in [56044] in which the path to core block styles are cached to avoid expensive file operations on every page load. The original caching strategy is now modified so that only the path relative to the blocks location are stored, rather than the full path, since the path to the `wp-includes` folder can change after the value is generated. The new cached value also includes the current WordPress version value to ensure it is rebuilt when the version changes.

Props lhe2012, coreyw, colorful tones, petitphp, mukesh27, spacedmonkey, joemcgill, flixos90, kimannwall, desmith.
Fixes #59111.



git-svn-id: https://develop.svn.wordpress.org/trunk@56524 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/blocks/index.php | 78 ++++++++++++++++++++++----------
 1 file changed, 55 insertions(+), 23 deletions(-)

diff --git a/src/wp-includes/blocks/index.php b/src/wp-includes/blocks/index.php
index 4a95b90351..a966248c79 100644
--- a/src/wp-includes/blocks/index.php
+++ b/src/wp-includes/blocks/index.php
@@ -20,46 +20,78 @@ require BLOCKS_PATH . 'require-dynamic-blocks.php';
  * avoids unnecessary logic and filesystem lookups in the other function.
  *
  * @since 6.3.0
+ *
+ * @global string $wp_version The WordPress version string.
  */
 function register_core_block_style_handles() {
+	global $wp_version;
+
 	if ( ! wp_should_load_separate_core_block_assets() ) {
 		return;
 	}
 
-	static $core_blocks_meta;
-	if ( ! $core_blocks_meta ) {
-		$core_blocks_meta = require ABSPATH . WPINC . '/blocks/blocks-json.php';
-	}
-
-	$includes_url  = includes_url();
-	$includes_path = ABSPATH . WPINC . '/';
-	$suffix        = wp_scripts_get_suffix();
-	$wp_styles     = wp_styles();
-	$style_fields  = array(
+	$blocks_url   = includes_url( 'blocks/' );
+	$suffix       = wp_scripts_get_suffix();
+	$wp_styles    = wp_styles();
+	$style_fields = array(
 		'style'       => 'style',
 		'editorStyle' => 'editor',
 	);
 
+	static $core_blocks_meta;
+	if ( ! $core_blocks_meta ) {
+		$core_blocks_meta = require BLOCKS_PATH . 'blocks-json.php';
+	}
+
+	$files          = false;
+	$transient_name = 'wp_core_block_css_files';
+
 	/*
 	 * Ignore transient cache when the development mode is set to 'core'. Why? To avoid interfering with
 	 * the core developer's workflow.
 	 */
-	if ( ! wp_is_development_mode( 'core' ) ) {
-		$transient_name = 'wp_core_block_css_files';
-		$files          = get_transient( $transient_name );
-		if ( ! $files ) {
-			$files = glob( wp_normalize_path( __DIR__ . '/**/**.css' ) );
-			set_transient( $transient_name, $files );
+	$can_use_cached = ! wp_is_development_mode( 'core' );
+
+	if ( $can_use_cached ) {
+		$cached_files = get_transient( $transient_name );
+
+		// Check the validity of cached values by checking against the current WordPress version.
+		if (
+			is_array( $cached_files )
+			&& isset( $cached_files['version'] )
+			&& $cached_files['version'] === $wp_version
+			&& isset( $cached_files['files'] )
+		) {
+			$files = $cached_files['files'];
 		}
-	} else {
-		$files = glob( wp_normalize_path( __DIR__ . '/**/**.css' ) );
 	}
 
-	$register_style = static function( $name, $filename, $style_handle ) use ( $includes_path, $includes_url, $suffix, $wp_styles, $files ) {
-		$style_path = "blocks/{$name}/{$filename}{$suffix}.css";
-		$path       = wp_normalize_path( $includes_path . $style_path );
+	if ( ! $files ) {
+		$files = glob( wp_normalize_path( BLOCKS_PATH . '**/**.css' ) );
+		$files = array_map(
+			static function ( $file ) {
+				return str_replace( BLOCKS_PATH, '', $file );
+			},
+			$files
+		);
 
-		if ( ! in_array( $path, $files, true ) ) {
+		// Save core block style paths in cache when not in development mode.
+		if ( $can_use_cached ) {
+			set_transient(
+				$transient_name,
+				array(
+					'version' => $wp_version,
+					'files'   => $files,
+				)
+			);
+		}
+	}
+
+	$register_style = static function( $name, $filename, $style_handle ) use ( $blocks_url, $suffix, $wp_styles, $files ) {
+		$style_path = "{$name}/{$filename}{$suffix}.css";
+		$path       = wp_normalize_path( BLOCKS_PATH . $style_path );
+
+		if ( ! in_array( $style_path, $files, true ) ) {
 			$wp_styles->add(
 				$style_handle,
 				false
@@ -67,7 +99,7 @@ function register_core_block_style_handles() {
 			return;
 		}
 
-		$wp_styles->add( $style_handle, $includes_url . $style_path );
+		$wp_styles->add( $style_handle, $blocks_url . $style_path );
 		$wp_styles->add_data( $style_handle, 'path', $path );
 
 		$rtl_file = str_replace( "{$suffix}.css", "-rtl{$suffix}.css", $path );