Ticket #39996: 39996.2.diff

src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php

@@ -574 +574 @@
                 }
 
                 if ( ! empty( $schema['properties']['template'] ) && isset( $request['template'] ) ) {
-                        $this->handle_template( $request['template'], $post_id );
+                        $this->handle_template( $request['template'], $post_id, true );
                 }
 
                 $terms_update = $this->handle_terms( $post_id, $request );
@@ -1071 +1071 @@
                         $prepared_post->ping_status = $request['ping_status'];
                 }
 
+                if ( ! empty( $schema['properties']['template'] ) ) {
+                        // Force template to null so that it can be handled exclusively by the REST controller.
+                        $prepared_post->page_template = null;
+                }
+
                 /**
                  * Filters a post before it is inserted via the REST API.
                  *
@@ -1148 +1153 @@
         }
 
         /**
+         * Check whether the template is valid for the given post.
+         *
+         * @since 4.9.0
+         *
+         * @param string          $template
+         * @param WP_REST_Request $request
+         *
+         * @return bool|WP_Error True if template is still valid or if the same as existing value, or false if template not supported.
+         */
+        public function check_template( $template, $request ) {
+
+                if ( ! $template ) {
+                        return true;
+                }
+
+                if ( $request['id'] ) {
+                        $current_template = get_page_template_slug( $request['id'] );
+                } else {
+                        $current_template = '';
+                }
+
+                // Always allow for updating a post to the same template, even if that template is no longer supported.
+                if ( $template === $current_template ) {
+                        return true;
+                }
+
+                // If this is a create request, get_post() will return null and wp theme will fallback to the passed post type.
+                $allowed_templates = wp_get_theme()->get_page_templates( get_post( $request['id'] ), $this->post_type );
+
+                if ( isset( $allowed_templates[ $template ] ) ) {
+                        return true;
+                }
+
+                /* translators: 1: parameter, 2: list of valid values */
+                return new WP_Error( 'rest_invalid_param', sprintf( __( '%1$s is not one of %2$s.' ), 'template', implode( ', ', array_keys( $allowed_templates ) ) ) );
+        }
+
+        /**
          * Sets the template for a post.
          *
          * @since 4.7.0
+         * @since 4.9.0 Introduced the $validate parameter.
          *
          * @param string  $template Page template filename.
          * @param integer $post_id  Post ID.
+         * @param bool    $validate Whether to validate that the template selected is valid.
          */
-        public function handle_template( $template, $post_id ) {
-                if ( in_array( $template, array_keys( wp_get_theme()->get_page_templates( get_post( $post_id ) ) ), true ) ) {
-                        update_post_meta( $post_id, '_wp_page_template', $template );
-                } else {
-                        update_post_meta( $post_id, '_wp_page_template', '' );
+        public function handle_template( $template, $post_id, $validate = false ) {
+
+                if ( $validate && ! array_key_exists( $template, wp_get_theme()->get_page_templates( get_post( $post_id ) ) ) ) {
+                        $template = '';
                 }
+
+                update_post_meta( $post_id, '_wp_page_template', $template );
         }
 
         /**
@@ -1996 +2042 @@
                 $schema['properties']['template'] = array(
                         'description' => __( 'The theme file to use to display the object.' ),
                         'type'        => 'string',
-                        'enum'        => array_merge( array_keys( wp_get_theme()->get_page_templates( null, $this->post_type ) ), array( '' ) ),
                         'context'     => array( 'view', 'edit' ),
+                        'arg_options' => array(
+                                'validate_callback' => array( $this, 'check_template' ),
+                        ),
                 );
 
                 $taxonomies = wp_list_filter( get_object_taxonomies( $this->post_type, 'objects' ), array( 'show_in_rest' => true ) );

tests/phpunit/tests/rest-api/rest-posts-controller.php

@@ -2667 +2667 @@
                 $this->assertEquals( '', $post_template );
         }
 
+        /**
+         * @ticket 39996
+         */
+        public function test_update_item_with_same_template_that_no_longer_exists() {
+
+                wp_set_current_user( self::$editor_id );
+
+                update_post_meta( self::$post_id, '_wp_page_template', 'post-my-invalid-template.php' );
+
+                $request = new WP_REST_Request( 'PUT', sprintf( '/wp/v2/posts/%d', self::$post_id ) );
+                $params = $this->set_post_data( array(
+                        'template' => 'post-my-invalid-template.php',
+                ) );
+                $request->set_body_params( $params );
+                $response = $this->server->dispatch( $request );
+
+                $this->assertEquals( 200, $response->get_status() );
+
+                $data = $response->get_data();
+                $post_template = get_page_template_slug( get_post( $data['id'] ) );
+
+                $this->assertEquals( 'post-my-invalid-template.php', $post_template );
+                $this->assertEquals( 'post-my-invalid-template.php', $data['template'] );
+        }
 
         public function verify_post_roundtrip( $input = array(), $expected_output = array() ) {
                 // Create the post