Scheduled Updates: Check if load function exists before using it. (#3…

…7081)

* Scheduled Updates: Check if load function exists before using it.

In #36915 we introduced an alternative load path for the endpoint file, which can lead to undefined function errors when loaded outside of the context of Jetpack.

* Fix up versions

* Remove unneeded collection callback

It doesn't do anything currently and creates fatal errors when update-schedules endpoints get called internally. Let's just remove it for now.

* Only call rest_get_server() if we're in a REST API request.

projects/packages/scheduled-updates/changelog/add-function-exists-check

@@ -0,0 +1,4 @@
+Significance: patch
+Type: added
+
+Adds an exists check before using wpcom_rest_api_v2_load_plugin() in the API endpoint.

projects/packages/scheduled-updates/src/class-scheduled-updates.php

@@ -20,7 +20,7 @@ class Scheduled_Updates {
 	 *
 	 * @var string
 	 */
-	const PACKAGE_VERSION = '0.9.0';
+	const PACKAGE_VERSION = '0.9.1-alpha';
 
 	/**
 	 * The cron event hook for the scheduled plugins update.

projects/packages/scheduled-updates/src/wpcom-endpoints/class-wpcom-rest-api-v2-endpoint-update-schedules.php

@@ -520,12 +520,16 @@ public function prepare_response_for_collection( $response ) {
 			return $response;
 		}
 
-		$data   = (array) $response->get_data();
-		$server = rest_get_server();
-		$links  = $server::get_compact_response_links( $response );
+		$data = (array) $response->get_data();
 
-		if ( ! empty( $links ) ) {
-			$data['_links'] = $links;
+		// Only call rest_get_server() if we're in a REST API request.
+		if ( did_action( 'rest_api_init' ) ) {
+			$server = rest_get_server();
+			$links  = $server::get_compact_response_links( $response );
+
+			if ( ! empty( $links ) ) {
+				$data['_links'] = $links;
+			}
 		}
 
 		return $data;
@@ -834,4 +838,6 @@ public function get_object_params() {
 	}
 }
 
-wpcom_rest_api_v2_load_plugin( 'WPCOM_REST_API_V2_Endpoint_Update_Schedules' );
+if ( function_exists( 'wpcom_rest_api_v2_load_plugin' ) ) {
+	wpcom_rest_api_v2_load_plugin( 'WPCOM_REST_API_V2_Endpoint_Update_Schedules' );
+}