Boost: Fix sometimes not correctly adding WP_CACHE to wp-config.php (#35632)

* Make adding WP_CACHE constant to wp-config.php more resilient

* Add changelog

Author: dilirity

projects/plugins/boost/app/modules/cache/Page_Cache_Setup.php

@@ -91,7 +91,7 @@ private static function create_advanced_cache() {
 	 */
 	private static function add_wp_cache_define() {
 		$content = file_get_contents( ABSPATH . 'wp-config.php' );
-		if ( preg_match( '#define\s*\(\s*[\'"]WP_CACHE[\'"]#', $content ) === 1 ) {
+		if ( preg_match( '#^\s*define\s*\(\s*[\'"]WP_CACHE[\'"]#m', $content ) === 1 ) {
 			/*
 			 * wp-settings.php checks "if ( WP_CACHE )" so it may be truthy and
 			 * not === true to pass that check.
@@ -105,8 +105,8 @@ private static function add_wp_cache_define() {
 
 			return true; // WP_CACHE already added.
 		}
-		$content = str_replace(
-			'<?php',
+		$content = preg_replace(
+			'#^<\?php#',
 			'<?php
 define( \'WP_CACHE\', true );',
 			$content

projects/plugins/boost/changelog/fix-cache-setup-wp-config-constant

@@ -0,0 +1,5 @@
+Significance: patch
+Type: fixed
+Comment: Fix not adding WP_CACHE to wp-config.php in some cases.
+
+