From d76a9ab293f6c95aa86a86149616e129ce4437d6 Mon Sep 17 00:00:00 2001
From: matidau <65836048+matidau@users.noreply.github.com>
Date: Wed, 17 May 2023 18:10:37 +1000
Subject: [PATCH] Check if $message returns false

Released under the GNU Affero General Public License (AGPL), version 3.
---
 src/lib/default/diffbackend/exportchangesdiff.php | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/lib/default/diffbackend/exportchangesdiff.php b/src/lib/default/diffbackend/exportchangesdiff.php
index ed2cc08d..112d6249 100644
--- a/src/lib/default/diffbackend/exportchangesdiff.php
+++ b/src/lib/default/diffbackend/exportchangesdiff.php
@@ -160,7 +160,8 @@ public function Synchronize() {
                         $message = $this->backend->GetMessage($this->folderid, $change["id"], $this->contentparameters);
 
                         // copy the flag to the message
-                        $message->flags = (isset($change["flags"])) ? $change["flags"] : 0;
+                        if($message)
+                            $message->flags = (isset($change["flags"])) ? $change["flags"] : 0;
 
                         if($stat && $message) {
                             if($this->flags & BACKEND_DISCARD_DATA || $this->importer->ImportMessageChange($change["id"], $message) == true)