Ticket #35658: 35658.30.diff

src/wp-includes/meta.php

@@ -1075 +1075 @@
                 }
         }
 
+        $object_subtype = '';
+
+        if ( ! empty( $args['object_subtype'] ) ) {
+                $object_subtype = $args['object_subtype'];
+        }
+
         // Back-compat: old sanitize and auth callbacks applied to all of an object type
         if ( $has_old_sanitize_cb ) {
                 add_filter( "sanitize_{$object_type}_meta_{$meta_key}", $args['sanitize_callback'], 10, 4 );
@@ -1090 +1096 @@
         }
 
         // Global registry only contains meta keys registered in the new way with a subtype.
-        if ( ! empty( $args['object_subtype'] ) ) {
-                $object_subtype = $args['object_subtype'];
+        if ( ! empty( $object_subtype ) ) {
                 $wp_meta_keys[ $object_type ][ $object_subtype ][ $meta_key ] = $args;
 
                 return true;