New helper functions, wp_cache_*_salted

src/wp-includes/cache-compat.php

@@ -199,3 +199,116 @@ function wp_cache_supports( $feature ) {
 		return false;
 	}
 endif;
+
+if ( ! function_exists( 'wp_cache_get_salted' ) ) :
+	/**
+	 * Retrieves cached data if valid and unchanged.
+	 *
+	 * @since 6.9.0
+	 *
+	 * @param string          $cache_key The cache key used for storage and retrieval.
+	 * @param string          $group     The cache group used for organizing data.
+	 * @param string|string[] $salt      The timestamp (or multiple timestamps if an array) indicating when the cache group(s) were last updated.
+	 * @return mixed|false The cached data if valid, or false if the cache does not exist or is outdated.
+	 */
+	function wp_cache_get_salted( $cache_key, $group, $salt ) {
+		$salt  = is_array( $salt ) ? implode( ':', $salt ) : $salt;
+		$cache = wp_cache_get( $cache_key, $group );
+
+		if ( ! is_array( $cache ) ) {
+			return false;
+		}
+
+		if ( ! isset( $cache['salt'] ) || ! isset( $cache['data'] ) || $salt !== $cache['salt'] ) {
+			return false;
+		}
+
+		return $cache['data'];
+	}
+endif;
+
+if ( ! function_exists( 'wp_cache_set_salted' ) ) :
+	/**
+	 * Stores salted data in the cache.
+	 *
+	 * @since 6.9.0
+	 *
+	 * @param string          $cache_key The cache key under which to store the data.
+	 * @param mixed           $data      The data to be cached.
+	 * @param string          $group     The cache group to which the data belongs.
+	 * @param string|string[] $salt The timestamp (or multiple timestamps if an array) indicating when the cache group(s) were last updated.
+	 * @param int             $expire    Optional. When to expire the cache contents, in seconds.
+	 *                                   Default 0 (no expiration).
+	 * @return bool True on success, false on failure.
+	 */
+	function wp_cache_set_salted( $cache_key, $data, $group, $salt, $expire = 0 ) {
+		$salt = is_array( $salt ) ? implode( ':', $salt ) : $salt;
+		return wp_cache_set(
+			$cache_key,
+			array(
+				'data' => $data,
+				'salt' => $salt,
+			),
+			$group,
+			$expire
+		);
+	}
+endif;
+
+if ( ! function_exists( 'wp_cache_get_multiple_salted' ) ) :
+	/**
+	 * Retrieves multiple items from the cache, only considering valid and unchanged items.
+	 *
+	 * @since 6.9.0
+	 *
+	 * @param array           $cache_keys Array of cache keys to retrieve.
+	 * @param string          $group      The group of the cache to check.
+	 * @param string|string[] $salt       The timestamp (or multiple timestamps if an array) indicating when the cache group(s) were last updated.
+	 * @return array An associative array containing cache values. Values are `false` if they are not found or outdated.
+	 */
+	function wp_cache_get_multiple_salted( $cache_keys, $group, $salt ) {
+		$salt  = is_array( $salt ) ? implode( ':', $salt ) : $salt;
+		$cache = wp_cache_get_multiple( $cache_keys, $group );
+
+		foreach ( $cache as $key => $value ) {
+			if ( ! is_array( $value ) ) {
+				$cache[ $key ] = false;
+				continue;
+			}
+			if ( ! isset( $value['salt'], $value['data'] ) || $salt !== $value['salt'] ) {
+				$cache[ $key ] = false;
+				continue;
+			}
+			$cache[ $key ] = $value['data'];
+		}
+
+		return $cache;
+	}
+endif;
+
+if ( ! function_exists( 'wp_cache_set_multiple_salted' ) ) :
+	/**
+	 * Stores multiple pieces of salted data in the cache.
+	 *
+	 * @since 6.9.0
+	 *
+	 * @param mixed           $data   Data to be stored in the cache for all keys.
+	 * @param string          $group  Group to which the cached data belongs.
+	 * @param string|string[] $salt   The timestamp (or multiple timestamps if an array) indicating when the cache group(s) were last updated.
+	 * @param int             $expire Optional. When to expire the cache contents, in seconds.
+	 *                                Default 0 (no expiration).
+	 * @return bool[] Array of return values, grouped by key. Each value is either
+	 *                true on success, or false on failure.
+	 */
+	function wp_cache_set_multiple_salted( $data, $group, $salt, $expire = 0 ) {
+		$salt      = is_array( $salt ) ? implode( ':', $salt ) : $salt;
+		$new_cache = array();
+		foreach ( $data as $key => $value ) {
+			$new_cache[ $key ] = array(
+				'data' => $value,
+				'salt' => $salt,
+			);
+		}
+		return wp_cache_set_multiple( $new_cache, $group, $expire );
+	}
+endif;

src/wp-includes/class-wp-comment-query.php

@@ -451,8 +451,8 @@ public function get_comments() {
 		$key          = md5( serialize( $_args ) );
 		$last_changed = wp_cache_get_last_changed( 'comment' );
 
-		$cache_key   = "get_comments:$key:$last_changed";
-		$cache_value = wp_cache_get( $cache_key, 'comment-queries' );
+		$cache_key   = "get_comments:$key";
+		$cache_value = wp_cache_get_salted( $cache_key, 'comment-queries', $last_changed );
 		if ( false === $cache_value ) {
 			$comment_ids = $this->get_comment_ids();
 			if ( $comment_ids ) {
@@ -463,7 +463,7 @@ public function get_comments() {
 				'comment_ids'    => $comment_ids,
 				'found_comments' => $this->found_comments,
 			);
-			wp_cache_add( $cache_key, $cache_value, 'comment-queries' );
+			wp_cache_set_salted( $cache_key, $cache_value, 'comment-queries', $last_changed );
 		} else {
 			$comment_ids          = $cache_value['comment_ids'];
 			$this->found_comments = $cache_value['found_comments'];
@@ -1044,9 +1044,9 @@ protected function fill_descendants( $comments ) {
 			if ( $_parent_ids ) {
 				$cache_keys = array();
 				foreach ( $_parent_ids as $parent_id ) {
-					$cache_keys[ $parent_id ] = "get_comment_child_ids:$parent_id:$key:$last_changed";
+					$cache_keys[ $parent_id ] = "get_comment_child_ids:$parent_id:$key";
 				}
-				$cache_data = wp_cache_get_multiple( array_values( $cache_keys ), 'comment-queries' );
+				$cache_data = wp_cache_get_multiple_salted( array_values( $cache_keys ), 'comment-queries', $last_changed );
 				foreach ( $_parent_ids as $parent_id ) {
 					$parent_child_ids = $cache_data[ $cache_keys[ $parent_id ] ];
 					if ( false !== $parent_child_ids ) {
@@ -1080,10 +1080,10 @@ protected function fill_descendants( $comments ) {
 
 				$data = array();
 				foreach ( $parent_map as $parent_id => $children ) {
-					$cache_key          = "get_comment_child_ids:$parent_id:$key:$last_changed";
+					$cache_key          = "get_comment_child_ids:$parent_id:$key";
 					$data[ $cache_key ] = $children;
 				}
-				wp_cache_set_multiple( $data, 'comment-queries' );
+				wp_cache_set_multiple_salted( $data, 'comment-queries', $last_changed );
 			}
 
 			++$level;

src/wp-includes/class-wp-network-query.php

@@ -249,8 +249,8 @@ public function get_networks() {
 		$key          = md5( serialize( $_args ) );
 		$last_changed = wp_cache_get_last_changed( 'networks' );
 
-		$cache_key   = "get_network_ids:$key:$last_changed";
-		$cache_value = wp_cache_get( $cache_key, 'network-queries' );
+		$cache_key   = "get_network_ids:$key";
+		$cache_value = wp_cache_get_salted( $cache_key, 'network-queries', $last_changed );
 
 		if ( false === $cache_value ) {
 			$network_ids = $this->get_network_ids();
@@ -262,7 +262,7 @@ public function get_networks() {
 				'network_ids'    => $network_ids,
 				'found_networks' => $this->found_networks,
 			);
-			wp_cache_add( $cache_key, $cache_value, 'network-queries' );
+			wp_cache_set_salted( $cache_key, $cache_value, 'network-queries', $last_changed );
 		} else {
 			$network_ids          = $cache_value['network_ids'];
 			$this->found_networks = $cache_value['found_networks'];

src/wp-includes/class-wp-query.php

@@ -2882,13 +2882,16 @@ public function get_posts() {
 			$comments_request = "SELECT $distinct {$wpdb->comments}.comment_ID FROM {$wpdb->comments} $cjoin $cwhere $cgroupby $corderby $climits";
 
 			$key          = md5( $comments_request );
-			$last_changed = wp_cache_get_last_changed( 'comment' ) . ':' . wp_cache_get_last_changed( 'posts' );
+			$last_changed = array(
+				wp_cache_get_last_changed( 'comment' ),
+				wp_cache_get_last_changed( 'posts' ),
+			);
 
-			$cache_key   = "comment_feed:$key:$last_changed";
-			$comment_ids = wp_cache_get( $cache_key, 'comment-queries' );
+			$cache_key   = "comment_feed:$key";
+			$comment_ids = wp_cache_get_salted( $cache_key, 'comment-queries', $last_changed );
 			if ( false === $comment_ids ) {
 				$comment_ids = $wpdb->get_col( $comments_request );
-				wp_cache_add( $cache_key, $comment_ids, 'comment-queries' );
+				wp_cache_set_salted( $cache_key, $comment_ids, 'comment-queries', $last_changed );
 			}
 			_prime_comment_caches( $comment_ids );
 
@@ -3246,15 +3249,21 @@ public function get_posts() {
 			$id_query_is_cacheable = false;
 		}
 
+		$last_changed = (array) wp_cache_get_last_changed( 'posts' );
+		if ( ! empty( $this->tax_query->queries ) ) {
+			$last_changed[] = wp_cache_get_last_changed( 'terms' );
+		}
+
 		if ( $q['cache_results'] && $id_query_is_cacheable ) {
 			$new_request = str_replace( $fields, "{$wpdb->posts}.*", $this->request );
 			$cache_key   = $this->generate_cache_key( $q, $new_request );
 
 			$cache_found = false;
 			if ( null === $this->posts ) {
-				$cached_results = wp_cache_get( $cache_key, 'post-queries', false, $cache_found );
+				$cached_results = wp_cache_get_salted( $cache_key, 'post-queries', $last_changed );
 
 				if ( $cached_results ) {
+					$cache_found = true;
 					/** @var int[] */
 					$post_ids = array_map( 'intval', $cached_results['posts'] );
 
@@ -3312,7 +3321,7 @@ public function get_posts() {
 					'max_num_pages' => $this->max_num_pages,
 				);
 
-				wp_cache_set( $cache_key, $cache_value, 'post-queries' );
+				wp_cache_set_salted( $cache_key, $cache_value, 'post-queries', $last_changed );
 			}
 
 			return $this->posts;
@@ -3350,7 +3359,7 @@ public function get_posts() {
 					'max_num_pages' => $this->max_num_pages,
 				);
 
-				wp_cache_set( $cache_key, $cache_value, 'post-queries' );
+				wp_cache_set_salted( $cache_key, $cache_value, 'post-queries', $last_changed );
 			}
 
 			return $post_parents;
@@ -3448,7 +3457,7 @@ public function get_posts() {
 				'max_num_pages' => $this->max_num_pages,
 			);
 
-			wp_cache_set( $cache_key, $cache_value, 'post-queries' );
+			wp_cache_set_salted( $cache_key, $cache_value, 'post-queries', $last_changed );
 		}
 
 		if ( ! $q['suppress_filters'] ) {
@@ -3486,11 +3495,11 @@ public function get_posts() {
 			$comment_key          = md5( $comments_request );
 			$comment_last_changed = wp_cache_get_last_changed( 'comment' );
 
-			$comment_cache_key = "comment_feed:$comment_key:$comment_last_changed";
-			$comment_ids       = wp_cache_get( $comment_cache_key, 'comment-queries' );
+			$comment_cache_key = "comment_feed:$comment_key";
+			$comment_ids       = wp_cache_get_salted( $comment_cache_key, 'comment-queries', $comment_last_changed );
 			if ( false === $comment_ids ) {
 				$comment_ids = $wpdb->get_col( $comments_request );
-				wp_cache_add( $comment_cache_key, $comment_ids, 'comment-queries' );
+				wp_cache_set_salted( $comment_cache_key, $comment_ids, 'comment-queries', $comment_last_changed );
 			}
 			_prime_comment_caches( $comment_ids );
 
@@ -5062,12 +5071,7 @@ static function ( &$value ) use ( $wpdb, $placeholder ) {
 		$sql = $wpdb->remove_placeholder_escape( $sql );
 		$key = md5( serialize( $args ) . $sql );
 
-		$last_changed = wp_cache_get_last_changed( 'posts' );
-		if ( ! empty( $this->tax_query->queries ) ) {
-			$last_changed .= wp_cache_get_last_changed( 'terms' );
-		}
-
-		$this->query_cache_key = "wp_query:$key:$last_changed";
+		$this->query_cache_key = "wp_query:$key";
 		return $this->query_cache_key;
 	}
 

src/wp-includes/class-wp-site-query.php

@@ -357,8 +357,8 @@ public function get_sites() {
 		$key          = md5( serialize( $_args ) );
 		$last_changed = wp_cache_get_last_changed( 'sites' );
 
-		$cache_key   = "get_sites:$key:$last_changed";
-		$cache_value = wp_cache_get( $cache_key, 'site-queries' );
+		$cache_key   = "get_sites:$key";
+		$cache_value = wp_cache_get_salted( $cache_key, 'site-queries', $last_changed );
 
 		if ( false === $cache_value ) {
 			$site_ids = $this->get_site_ids();
@@ -370,7 +370,7 @@ public function get_sites() {
 				'site_ids'    => $site_ids,
 				'found_sites' => $this->found_sites,
 			);
-			wp_cache_add( $cache_key, $cache_value, 'site-queries' );
+			wp_cache_set_salted( $cache_key, $cache_value, 'site-queries', $last_changed );
 		} else {
 			$site_ids          = $cache_value['site_ids'];
 			$this->found_sites = $cache_value['found_sites'];

src/wp-includes/class-wp-term-query.php

@@ -777,8 +777,9 @@ public function get_terms() {
 		}
 
 		if ( $args['cache_results'] ) {
-			$cache_key = $this->generate_cache_key( $args, $this->request );
-			$cache     = wp_cache_get( $cache_key, 'term-queries' );
+			$cache_key    = $this->generate_cache_key( $args, $this->request );
+			$last_changed = wp_cache_get_last_changed( 'terms' );
+			$cache        = wp_cache_get_salted( $cache_key, 'term-queries', $last_changed );
 
 			if ( false !== $cache ) {
 				if ( 'ids' === $_fields ) {
@@ -806,7 +807,7 @@ public function get_terms() {
 		if ( 'count' === $_fields ) {
 			$count = $wpdb->get_var( $this->request ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
 			if ( $args['cache_results'] ) {
-				wp_cache_set( $cache_key, $count, 'term-queries' );
+				wp_cache_set_salted( $cache_key, $count, 'term-queries', $last_changed );
 			}
 			return $count;
 		}
@@ -815,7 +816,7 @@ public function get_terms() {
 
 		if ( empty( $terms ) ) {
 			if ( $args['cache_results'] ) {
-				wp_cache_add( $cache_key, array(), 'term-queries' );
+				wp_cache_set_salted( $cache_key, array(), 'term-queries', $last_changed );
 			}
 			return array();
 		}
@@ -899,7 +900,7 @@ public function get_terms() {
 		}
 
 		if ( $args['cache_results'] ) {
-			wp_cache_add( $cache_key, $term_cache, 'term-queries' );
+			wp_cache_set_salted( $cache_key, $term_cache, 'term-queries', $last_changed );
 		}
 
 		$this->terms = $this->format_terms( $term_objects, $_fields );
@@ -1171,8 +1172,8 @@ protected function generate_cache_key( array $args, $sql ) {
 		// Replace wpdb placeholder in the SQL statement used by the cache key.
 		$sql = $wpdb->remove_placeholder_escape( $sql );
 
-		$key          = md5( serialize( $cache_args ) . $sql );
-		$last_changed = wp_cache_get_last_changed( 'terms' );
-		return "get_terms:$key:$last_changed";
+		$key = md5( serialize( $cache_args ) . $sql );
+
+		return "get_terms:$key";
 	}
 }