ZP-279 #comment check if in failstate an entry for the client id is available #time 20m

git-svn-id: https://z-push.org/svn/z-push/trunk@1545 b7dd7b3b-3a3c-0410-9da9-bee62a6cc5b5

src/lib/request/sync.php

@@ -1052,7 +1052,7 @@ class Sync extends RequestProcessor {
         $ignoreMessage = false;
         if ($actiondata["failstate"]) {
             // message was ADDED before, do NOT add it again
-            if ($todo == SYNC_ADD && $actiondata["failstate"]["clientids"][$clientid]) {
+            if ($todo == SYNC_ADD && isset($actiondata["failstate"]["clientids"][$clientid])) {
                 $ignoreMessage = true;
 
                 // make sure no messages are sent back