Changeset 63354 for trunk/src/wp-includes/class-wp-site.php

Timestamp:

08/26/2026 10:20:49 PM (3 days ago)

Author:

westonruter

Message:

Cache API: Treat an unusable cached value as a miss.

WP_Site::get_instance() treated only false as a cache miss, but wp_cache_get() can return whatever a persistent object cache holds under that key. A cached string or array therefore skipped the refetch and reached the constructor, where get_object_vars() raised a TypeError. The same lookup is repeated in WP_Network::get_instance(), WP_Post::get_instance(), WP_Comment::get_instance() and WP_Term::get_instance(); networks and terms carried the identical fatal.

All five now refetch unless the cached value is an object carrying the property that identifies it. That also closes a quieter bug in the same code: an object missing that property was accepted as a cache hit, so posts came back with an ID of 0, comments with a null comment_ID, and terms as an entirely different term. Sites and networks keep their -1 sentinel recording a lookup that previously found nothing.

The refetched row is now stored with wp_cache_set() rather than wp_cache_add(). Widening the guard makes the branch reachable while an entry is still present, and add() does not overwrite, so the unusable value survived and every later lookup for that object queried the database again.

Developed in ​https://github.com/WordPress/wordpress-develop/pull/13270.
Follow-up to r33891, r35537, r45910, r62648.

Props josephscott, westonruter.
Fixes #65962.

File:

• trunk/src/wp-includes/class-wp-site.php (modified) (3 diffs)

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

@@ -160 +160 @@
          *
          * @since 4.5.0
+         * @since 7.2.0 Cache values that are neither a site object nor the -1 miss sentinel are now treated as a cache miss and replaced.
          *
          * @global wpdb $wpdb WordPress database abstraction object.
@@ -176 +177 @@
                 $_site = wp_cache_get( $site_id, 'sites' );
 
-                if ( false === $_site ) {
+                // A cached -1 records a previous lookup that found nothing. Any other non-numeric value that is not a site object is treated as a cache miss.
+                if (
+                        ( ! is_object( $_site ) || ! isset( $_site->blog_id ) )
+                        &&
+                        ! is_numeric( $_site )
+                ) {
                         $_site = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM {$wpdb->blogs} WHERE blog_id = %d LIMIT 1", $site_id ) );
 
@@ -183 +189 @@
                         }
 
-                        wp_cache_add( $site_id, $_site, 'sites' );
+                        // Not wp_cache_add(), since an unusable cached value may still be present and must be replaced.
+                        wp_cache_set( $site_id, $_site, 'sites' );
                 }