From 1ea3147567f1acb3b8241a2a405b380bdc5b95a5 Mon Sep 17 00:00:00 2001
From: Ryan Wyllie <ryan@moodle.com>
Date: Mon, 27 Mar 2017 05:49:27 +0000
Subject: [PATCH] MDL-58332 message: remove concat in get_popup_notifications
 sql

Removed the concat to generate the uniqueid field for the popup
notifications data. The concat can't be used directly in the SQL because
the syntax changes between databases. The sql_concat helper can't be
used because it assumes all values are database columns (which they
aren't in this case).

Instead I've just removed the uniqueid field because it isn't required
for the union all to work and the field isn't being used by anything.
This should fixed the compatibility issues between databases.
---
 message/output/popup/classes/api.php | 52 ++++++++++++++++------------
 1 file changed, 30 insertions(+), 22 deletions(-)

diff --git a/message/output/popup/classes/api.php b/message/output/popup/classes/api.php
index 66908154612..84826f61981 100644
--- a/message/output/popup/classes/api.php
+++ b/message/output/popup/classes/api.php
@@ -73,29 +73,37 @@ class api {
             return array();
         }
 
-        $sql = "SELECT * FROM (
-                    SELECT concat('r', r.id) as uniqueid, r.id, r.useridfrom, r.useridto,
-                        r.subject, r.fullmessage, r.fullmessageformat,
-                        r.fullmessagehtml, r.smallmessage, r.notification, r.contexturl,
-                        r.contexturlname, r.timecreated, r.timeuserfromdeleted, r.timeusertodeleted,
-                        r.component, r.eventtype, r.timeread
-                    FROM {message_read} r
-                    WHERE r.notification = 1
-                    AND r.id IN (SELECT messageid FROM {message_popup} WHERE isread = 1)
-                    AND r.useridto = :useridto1
-                UNION ALL
-                    SELECT concat('u', u.id) as uniqueid, u.id, u.useridfrom, u.useridto,
-                        u.subject, u.fullmessage, u.fullmessageformat,
-                        u.fullmessagehtml, u.smallmessage, u.notification, u.contexturl,
-                        u.contexturlname, u.timecreated, u.timeuserfromdeleted, u.timeusertodeleted,
-                        u.component, u.eventtype, 0 as timeread
-                    FROM {message} u
-                    WHERE u.notification = 1
-                    AND u.id IN (SELECT messageid FROM {message_popup} WHERE isread = 0)
-                    AND u.useridto = :useridto2
-                ) f ORDER BY timecreated $sort, timeread $sort, id $sort";
+        $sql = "SELECT r.id, r.useridfrom, r.useridto,
+                       r.subject, r.fullmessage, r.fullmessageformat,
+                       r.fullmessagehtml, r.smallmessage, r.notification, r.contexturl,
+                       r.contexturlname, r.timecreated, r.timeuserfromdeleted, r.timeusertodeleted,
+                       r.component, r.eventtype, r.timeread
+                  FROM {message_read} r
+                 WHERE r.notification = 1
+                       AND r.id IN (SELECT messageid FROM {message_popup} WHERE isread = 1)
+                       AND r.useridto = :useridto1
+             UNION ALL
+                SELECT u.id, u.useridfrom, u.useridto,
+                       u.subject, u.fullmessage, u.fullmessageformat,
+                       u.fullmessagehtml, u.smallmessage, u.notification, u.contexturl,
+                       u.contexturlname, u.timecreated, u.timeuserfromdeleted, u.timeusertodeleted,
+                       u.component, u.eventtype, 0 as timeread
+                  FROM {message} u
+                 WHERE u.notification = 1
+                       AND u.id IN (SELECT messageid FROM {message_popup} WHERE isread = 0)
+                       AND u.useridto = :useridto2
+              ORDER BY timecreated $sort, timeread $sort, id $sort";
 
-        return array_values($DB->get_records_sql($sql, $params, $offset, $limit));
+        $notifications = [];
+        // Use recordset here to ensure records with the same id aren't ignored because
+        // we can have id clashes between the message and message_read tables.
+        $records = $DB->get_recordset_sql($sql, $params, $offset, $limit);
+        foreach ($records as $record) {
+            $notifications[] = (object) $record;
+        }
+        $records->close();
+
+        return $notifications;
     }
 
     /**