Ticket #21755: 21755.diff

wp-includes/post.php

@@ -2776 +2776 @@
 
         if ( !empty($page_template) && 'page' == $data['post_type'] ) {
                 $post->page_template = $page_template;
-                $page_templates = get_page_templates();
-                if ( 'default' != $page_template && !in_array($page_template, $page_templates) ) {
+                $page_templates = wp_get_theme()->get_page_templates();
+                if ( 'default' != $page_template && ! isset( $page_templates[ $page_template ] ) ) {
                         if ( $wp_error )
                                 return new WP_Error('invalid_page_template', __('The page template is invalid.'));
                         else