Ticket #20376: 20376.4.patch

wp-includes/post.php

@@ -3685 +3685 @@
 
         $join = '';
         $where = "$exclusions $inclusions ";
-        if ( ! empty( $meta_key ) || ! empty( $meta_value ) ) {
+        if ( '' != $meta_key || '' != $meta_value ) {
                 $join = " LEFT JOIN $wpdb->postmeta ON ( $wpdb->posts.ID = $wpdb->postmeta.post_id )";
 
                 // meta_key and meta_value might be slashed
                 $meta_key = wp_unslash($meta_key);
                 $meta_value = wp_unslash($meta_value);
-                if ( ! empty( $meta_key ) )
+                if ( '' != $meta_key )
                         $where .= $wpdb->prepare(" AND $wpdb->postmeta.meta_key = %s", $meta_key);
-                if ( ! empty( $meta_value ) )
+                if ( '' != $meta_value )
                         $where .= $wpdb->prepare(" AND $wpdb->postmeta.meta_value = %s", $meta_value);
 
         }