From 522fcf2ffc1cbc32add2b11705bd9f83d45f210b Mon Sep 17 00:00:00 2001
From: Mark Nelson <markn@moodle.com>
Date: Thu, 22 Dec 2016 12:41:32 +0800
Subject: [PATCH] MDL-55955 mod_quiz: ensure duplicated override events are
 removed

---
 mod/quiz/lib.php | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/mod/quiz/lib.php b/mod/quiz/lib.php
index fd2b5791412..7652d2eea3b 100644
--- a/mod/quiz/lib.php
+++ b/mod/quiz/lib.php
@@ -1194,8 +1194,11 @@ function quiz_update_events($quiz, $override = null) {
                    'instance'=>$quiz->id);
     if (!empty($override)) {
         // Only load events for this override.
-        $conds['groupid'] = isset($override->groupid)?  $override->groupid : 0;
-        $conds['userid'] = isset($override->userid)?  $override->userid : 0;
+        if (isset($override->userid)) {
+            $conds['userid'] = $override->userid;
+        } else if (isset($override->groupid)) {
+            $conds['groupid'] = $override->groupid;
+        }
     }
     $oldevents = $DB->get_records('event', $conds);