REST API: Return an error if the page number is out of bounds.

Return an error from the REST API if a page number larger than the total pages count is requested.

Props morganestes.
Fixes #39061.
Built from https://develop.svn.wordpress.org/trunk@39967


git-svn-id: http://core.svn.wordpress.org/trunk@39904 1a063a9b-81f0-0310-95a4-ce76da25c4cd

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

@@ -327,6 +327,11 @@ class WP_REST_Posts_Controller extends WP_REST_Controller {
 		}
 
 		$max_pages = ceil( $total_posts / (int) $posts_query->query_vars['posts_per_page'] );
+
+		if ( $page > $max_pages && $total_posts > 0 ) {
+			return new WP_Error( 'rest_post_invalid_page_number', __( 'The page number requested is larger than the number of pages available.' ), array( 'status' => 400 ) );
+		}
+
 		$response  = rest_ensure_response( $posts );
 
 		$response->header( 'X-WP-Total', (int) $total_posts );

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.8-alpha-39956';
+$wp_version = '4.8-alpha-39967';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.