Merge branch 'MDL-67947_37' of https://github.com/timhunt/moodle into MOODLE_37_STABLE

lib/questionlib.php

@@ -119,34 +119,32 @@ function question_save_qtype_order($neworder, $config = null) {
  * @return boolean whether any of these questions are being used by any part of Moodle.
  */
 function questions_in_use($questionids) {
-    global $CFG;
 
+    // Are they used by the core question system?
     if (question_engine::questions_in_use($questionids)) {
         return true;
     }
 
-    foreach (core_component::get_plugin_list('mod') as $module => $path) {
-        $lib = $path . '/lib.php';
-        if (is_readable($lib)) {
-            include_once($lib);
+    // Check if any plugins are using these questions.
+    $callbacksbytype = get_plugins_with_function('questions_in_use');
+    foreach ($callbacksbytype as $callbacks) {
+        foreach ($callbacks as $function) {
+            if ($function($questionids)) {
+                return true;
+            }
+        }
+    }
 
-            $fn = $module . '_questions_in_use';
-            if (function_exists($fn)) {
-                if ($fn($questionids)) {
-                    return true;
-                }
-            } else {
+    // Finally check legacy callback.
+    $legacycallbacks = get_plugin_list_with_function('mod', 'question_list_instances');
+    foreach ($legacycallbacks as $plugin => $function) {
+        if (isset($callbacksbytype['mod'][substr($plugin, 4)])) {
+            continue; // Already done.
+        }
 
-                // Fallback for legacy modules.
-                $fn = $module . '_question_list_instances';
-                if (function_exists($fn)) {
-                    foreach ($questionids as $questionid) {
-                        $instances = $fn($questionid);
-                        if (!empty($instances)) {
-                            return true;
-                        }
-                    }
-                }
+        foreach ($questionids as $questionid) {
+            if (!empty($function($questionid))) {
+                return true;
             }
         }
     }