From a66de3ca7098f6cd7d2b201f935748f949e75f5d Mon Sep 17 00:00:00 2001
From: Damyon Wiese <damyon@moodle.com>
Date: Wed, 25 Oct 2017 15:42:14 +0800
Subject: [PATCH] MDL-59909 calendar: Try hard not to fail the adhoc task.

Triggering a fatal error in an adhoc task is bad. It will be retried indefinitely.
Even though we are not sure how to get a module instance without a course module record,
it is possible and should not kill the Moodle site.
---
 completion/classes/api.php                            | 5 ++++-
 completion/tests/api_test.php                         | 7 +++++++
 course/lib.php                                        | 9 ++++++---
 lib/classes/task/refresh_mod_calendar_events_task.php | 4 ++++
 4 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/completion/classes/api.php b/completion/classes/api.php
index 3bc469b1ae2a8..f8040c5864cc7 100644
--- a/completion/classes/api.php
+++ b/completion/classes/api.php
@@ -59,7 +59,10 @@ public static function update_completion_date_event($cmid, $modulename, $instanc
         if (is_object($instanceorid)) {
             $instance = $instanceorid;
         } else {
-            $instance = $DB->get_record($modulename, array('id' => $instanceorid), '*', MUST_EXIST);
+            $instance = $DB->get_record($modulename, array('id' => $instanceorid), '*', IGNORE_MISSING);
+        }
+        if (!$instance) {
+            return false;
         }
         $course = get_course($instance->course);
 
diff --git a/completion/tests/api_test.php b/completion/tests/api_test.php
index 489d0d03694d1..af24c079a8416 100644
--- a/completion/tests/api_test.php
+++ b/completion/tests/api_test.php
@@ -72,6 +72,13 @@ public function test_update_completion_date_event() {
         $this->assertEquals(\core_completion\api::COMPLETION_EVENT_TYPE_DATE_COMPLETION_EXPECTED, $event->eventtype);
         $this->assertEquals($time, $event->timestart);
         $this->assertEquals($time, $event->timesort);
+
+        require_once($CFG->dirroot . '/course/lib.php');
+        // Delete the module.
+        course_delete_module($assign->cmid);
+
+        // Check we don't get a failure when called on a deleted module.
+        \core_completion\api::update_completion_date_event($assign->cmid, 'assign', null, $time);
     }
 
     public function test_update_completion_date_event_update() {
diff --git a/course/lib.php b/course/lib.php
index c68879115134d..d0ad4f0660a49 100644
--- a/course/lib.php
+++ b/course/lib.php
@@ -1404,7 +1404,9 @@ function course_module_update_calendar_events($modulename, $instance = null, $cm
         if (!isset($cm)) {
             $cm = get_coursemodule_from_instance($modulename, $instance->id, $instance->course);
         }
-        course_module_calendar_event_update_process($instance, $cm);
+        if (!empty($cm)) {
+            course_module_calendar_event_update_process($instance, $cm);
+        }
         return true;
     }
     return false;
@@ -1433,8 +1435,9 @@ function course_module_bulk_update_calendar_events($modulename, $courseid = 0) {
     }
 
     foreach ($instances as $instance) {
-        $cm = get_coursemodule_from_instance($modulename, $instance->id, $instance->course);
-        course_module_calendar_event_update_process($instance, $cm);
+        if ($cm = get_coursemodule_from_instance($modulename, $instance->id, $instance->course)) {
+            course_module_calendar_event_update_process($instance, $cm);
+        }
     }
     return true;
 }
diff --git a/lib/classes/task/refresh_mod_calendar_events_task.php b/lib/classes/task/refresh_mod_calendar_events_task.php
index 2e967545f18f3..3e2641aea06cd 100644
--- a/lib/classes/task/refresh_mod_calendar_events_task.php
+++ b/lib/classes/task/refresh_mod_calendar_events_task.php
@@ -44,6 +44,10 @@ class refresh_mod_calendar_events_task extends adhoc_task {
      * Run the task to refresh calendar events.
      */
     public function execute() {
+        global $CFG;
+
+        require_once($CFG->dirroot . '/course/lib.php');
+
         // Specific list of plugins that need to be refreshed. If not set, then all mod plugins will be refreshed.
         $pluginstorefresh = null;
         if (isset($this->get_custom_data()->plugins)) {