From 545163440b2968af10b603229653a57857b94a41 Mon Sep 17 00:00:00 2001
From: Michael Aherne <michael.aherne@strath.ac.uk>
Date: Thu, 8 Oct 2015 14:39:27 +0100
Subject: [PATCH] MDL-51707 cron: Prevent finished tasks being returned

---
 lib/classes/task/manager.php | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/classes/task/manager.php b/lib/classes/task/manager.php
index 24852e15a0d..a06a4517b49 100644
--- a/lib/classes/task/manager.php
+++ b/lib/classes/task/manager.php
@@ -491,6 +491,12 @@ class manager {
                     }
                 }
 
+                // Make sure the task data is unchanged.
+                if (!$DB->record_exists('task_scheduled', (array) $record)) {
+                    $lock->release();
+                    continue;
+                }
+
                 if (!$task->is_blocking()) {
                     $cronlock->release();
                 } else {