MDL-31633 grades: Fixing incorrect redirect when trying to edit grade…

… letters from admin settings

grade/lib.php

@@ -2610,16 +2610,23 @@ public static function get_info_edit_structure($courseid) {
      * @return array
      */
     public static function get_info_letters($courseid) {
+        global $SITE;
         if (self::$letterinfo !== null) {
             return self::$letterinfo;
         }
         $context = context_course::instance($courseid);
         $canmanage = has_capability('moodle/grade:manage', $context);
         $canmanageletters = has_capability('moodle/grade:manageletters', $context);
         if ($canmanage || $canmanageletters) {
+            // Redirect to system context when report is accessed from admin settings MDL-31633
+            if ($context->instanceid == $SITE->id) {
+                $param = array('edit' => 1);
+            } else {
+                $param = array('edit' => 1,'id' => $context->id);
+            }
             self::$letterinfo = array(
                 'view' => new grade_plugin_info('view', new moodle_url('/grade/edit/letter/index.php', array('id'=>$context->id)), get_string('view')),
-                'edit' => new grade_plugin_info('edit', new moodle_url('/grade/edit/letter/index.php', array('edit'=>1,'id'=>$context->id)), get_string('edit'))
+                'edit' => new grade_plugin_info('edit', new moodle_url('/grade/edit/letter/index.php', $param), get_string('edit'))
             );
         } else {
             self::$letterinfo = false;