From 79e8411dc2b2777ae16a1511f75da30a542c8f44 Mon Sep 17 00:00:00 2001
From: stronk7 <stronk7>
Date: Fri, 28 Dec 2007 19:14:01 +0000
Subject: [PATCH] Prevent race condition in event creation. MDL-5956. Credit
 goes to Penny, Luke and Martin @ Catalyst.

Merged from MOODLE_19_STABLE
---
 backup/restorelib.php | 29 ++++++++++++++++-------------
 calendar/event.php    | 11 ++++++-----
 2 files changed, 22 insertions(+), 18 deletions(-)

diff --git a/backup/restorelib.php b/backup/restorelib.php
index 353cb40a41..1af2ee4ce9 100644
--- a/backup/restorelib.php
+++ b/backup/restorelib.php
@@ -3250,19 +3250,6 @@ define('RESTORE_GROUPS_GROUPINGS', 3);
                                 $eve->userid = $adminid;
                             }
 
-                            //We must recode the repeatid if the event has it
-                            if (!empty($eve->repeatid)) {
-                                $repeat_rec = backup_getid($restore->backup_unique_code,"event_repeatid",$eve->repeatid);
-                                if ($repeat_rec) {    //Exists, so use it...
-                                    $eve->repeatid = $repeat_rec->new_id;
-                                } else {              //Doesn't exists, calculate the next and save it
-                                    $oldrepeatid = $eve->repeatid;
-                                    $max_rec = get_record_sql('SELECT 1, MAX(repeatid) AS repeatid FROM '.$CFG->prefix.'event');
-                                    $eve->repeatid = empty($max_rec) ? 1 : $max_rec->repeatid + 1;
-                                    backup_putid($restore->backup_unique_code,"event_repeatid", $oldrepeatid, $eve->repeatid);
-                                }
-                            }
-
                             //We have to recode the groupid field
                             $group = backup_getid($restore->backup_unique_code,"groups",$eve->groupid);
                             if ($group) {
@@ -3274,6 +3261,22 @@ define('RESTORE_GROUPS_GROUPINGS', 3);
 
                             //The structure is equal to the db, so insert the event
                             $newid = insert_record ("event",$eve);
+
+                            //We must recode the repeatid if the event has it
+                            //The repeatid now refers to the id of the original event. (see Bug#5956)
+                            if ($newid && !empty($eve->repeatid)) {
+                                $repeat_rec = backup_getid($restore->backup_unique_code,"event_repeatid",$eve->repeatid);
+                                if ($repeat_rec) {    //Exists, so use it...
+                                    $eve->repeatid = $repeat_rec->new_id;
+                                } else {              //Doesn't exists, calculate the next and save it
+                                    $oldrepeatid = $eve->repeatid;
+                                    $eve->repeatid = $newid;
+                                    backup_putid($restore->backup_unique_code,"event_repeatid", $oldrepeatid, $eve->repeatid);
+                                }
+                                $eve->id = $newid;
+                                // update the record to contain the correct repeatid
+                                update_record('event',$eve);
+                            }
                         } else {
                             //get current event id
                             $newid = $eve_db->id;
diff --git a/calendar/event.php b/calendar/event.php
index bc37b72d44..ac650ac810 100644
--- a/calendar/event.php
+++ b/calendar/event.php
@@ -217,13 +217,14 @@
                 if (count($err) == 0) {
                     $form->timemodified = time();
 
-                    if ($form->repeat) {
-                        $fetch = get_record_sql('SELECT 1, MAX(repeatid) AS repeatid FROM '.$CFG->prefix.'event');
-                        $form->repeatid = empty($fetch) ? 1 : $fetch->repeatid + 1;
-                    }
-
                     /// Get the event id for the log record.
                     $eventid = insert_record('event', $form, true);
+                    
+                    /// Use the event id as the repeatid to link repeat entries together
+                    if ($form->repeat) {
+                        $form->repeatid = $form->id = $eventid;
+                        update_record('event', $form);         // update the row, to set its repeatid        	
+                    }
 
                     /// Log the event entry.
                     add_to_log($form->courseid, 'calendar', 'add', 'event.php?action=edit&amp;id='.$eventid, stripslashes($form->name));
-- 
2.39.5