Merge branch 'm501-86376' of https://github.com/danmarsden/moodle into MOODLE_501_STABLE

public/lib/classes/component.php

@@ -1376,6 +1376,7 @@ $cache = ' . var_export($cache, true) . ';
     public static function get_plugin_list_with_file($plugintype, $file, $include = false) {
         global $CFG; // Necessary in case it is referenced by included PHP scripts.
         $pluginfiles = [];
+        self::init();
 
         if (isset(self::$filemap[$file])) {
             // If the file was supposed to be mapped, then it should have been set in the array.
@@ -1417,6 +1418,7 @@ $cache = ' . var_export($cache, true) . ';
     public static function get_component_classes_in_namespace($component = null, $namespace = '') {
 
         $classes = [];
+        self::init();
 
         // Only look for components if a component name is set or a namespace is set.
         if (isset($component) || !empty($namespace)) {
@@ -1825,6 +1827,7 @@ $cache = ' . var_export($cache, true) . ';
      * @return bool true if core subsystem.
      */
     public static function is_core_subsystem($subsystemname) {
+        self::init();
         return isset(self::$subsystems[$subsystemname]);
     }
 
@@ -1835,6 +1838,7 @@ $cache = ' . var_export($cache, true) . ';
      * @return bool true if core API.
      */
     public static function is_core_api($apiname) {
+        self::init();
         return isset(self::$apis[$apiname]);
     }