From ff3ea55f76d0c000a203e769361e323a4308748e Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov.ru@gmail.com>
Date: Mon, 17 Dec 2018 03:29:47 +0000
Subject: [PATCH] REST API: Include fields with null schema in
 `get_fields_for_response()`.

In [43736], we prevented rendering fields when not present in `?_fields=`. However, because `get_fields_for_response()` is dependent on `get_item_schema()`, any custom fields registered with a null schema would be incorrectly excluded from the response. Because the REST API permits a null schema for `register_rest_field()`, those fields should be included in the available fields for a response.

Props danielbachhuber.
Merges [43908] to trunk.
Fixes #45220.
Built from https://develop.svn.wordpress.org/trunk@44254


git-svn-id: http://core.svn.wordpress.org/trunk@44084 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 .../rest-api/endpoints/class-wp-rest-controller.php    | 10 ++++++++++
 wp-includes/version.php                                |  2 +-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/wp-includes/rest-api/endpoints/class-wp-rest-controller.php b/wp-includes/rest-api/endpoints/class-wp-rest-controller.php
index 389262274f..6dc971517d 100644
--- a/wp-includes/rest-api/endpoints/class-wp-rest-controller.php
+++ b/wp-includes/rest-api/endpoints/class-wp-rest-controller.php
@@ -519,6 +519,16 @@ abstract class WP_REST_Controller {
 	public function get_fields_for_response( $request ) {
 		$schema = $this->get_item_schema();
 		$fields = isset( $schema['properties'] ) ? array_keys( $schema['properties'] ) : array();
+
+		$additional_fields = $this->get_additional_fields();
+		foreach ( $additional_fields as $field_name => $field_options ) {
+			// For back-compat, include any field with an empty schema
+			// because it won't be present in $this->get_item_schema().
+			if ( is_null( $field_options['schema'] ) ) {
+				$fields[] = $field_name;
+			}
+		}
+
 		if ( ! isset( $request['_fields'] ) ) {
 			return $fields;
 		}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 74f6dd8723..30b4a4d53d 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44253';
+$wp_version = '5.1-alpha-44254';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.