MDL-46651 Backup: Handle duplicate course completions during restore

Cron can cause duplicate completion records if triggered during a long
running restore process. If this is the case, replace the new record
with the record from the backup file

backup/moodle2/restore_stepslib.php

@@ -2607,7 +2607,21 @@ public function process_course_completions($data) {
                 'timecompleted' => $this->apply_date_offset($data->timecompleted),
                 'reaggregate' => $data->reaggregate
             );
-            $DB->insert_record('course_completions', $params);
+
+            $existing = $DB->get_record('course_completions', array(
+                'userid' => $data->userid,
+                'course' => $data->course
+            ));
+
+            // MDL-46651 - If cron writes out a new record before we get to it
+            // then we should replace it with the Truth data from the backup.
+            // This may be obsolete after MDL-48518 is resolved
+            if ($existing) {
+                $params['id'] = $existing->id;
+                $DB->update_record('course_completions', $params);
+            } else {
+                $DB->insert_record('course_completions', $params);
+            }
         }
     }