From 6f988b712dc0a3565044f21610fb19ce5390e095 Mon Sep 17 00:00:00 2001
From: Tim Hunt <T.J.Hunt@open.ac.uk>
Date: Tue, 13 May 2014 13:35:39 +0100
Subject: [PATCH] MDL-45455 quiz cron must rollback transaction on error.

---
 mod/quiz/cronlib.php | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mod/quiz/cronlib.php b/mod/quiz/cronlib.php
index 175e5c6a1ac..51509e7a95c 100644
--- a/mod/quiz/cronlib.php
+++ b/mod/quiz/cronlib.php
@@ -84,6 +84,9 @@ class mod_quiz_overdue_attempt_updater {
                 mtrace("Error while processing attempt {$attempt->id} at {$attempt->quiz} quiz:");
                 mtrace($e->getMessage());
                 mtrace($e->getTraceAsString());
+                // Close down any currently open transactions, otherwise one error
+                // will stop following DB changes from being committed.
+                $DB->force_transaction_rollback();
             }
         }