From 447645af2a689e8571f18f296c85f1f76a1290fa Mon Sep 17 00:00:00 2001
From: =?utf8?q?Tim=20D=C3=BCsterhus?= <duesterhus@woltlab.com>
Date: Thu, 23 Sep 2021 12:08:02 +0200
Subject: [PATCH] Prevent method calls on `null` in
 ConversationMessageAttachmentObjectType::canDownload()

This may happen for attachments where the corresponding conversation /
conversation message no longer exists.
---
 .../ConversationMessageAttachmentObjectType.class.php           | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/files/lib/system/attachment/ConversationMessageAttachmentObjectType.class.php b/files/lib/system/attachment/ConversationMessageAttachmentObjectType.class.php
index ce7e96d..621c1ed 100644
--- a/files/lib/system/attachment/ConversationMessageAttachmentObjectType.class.php
+++ b/files/lib/system/attachment/ConversationMessageAttachmentObjectType.class.php
@@ -55,7 +55,7 @@ class ConversationMessageAttachmentObjectType extends AbstractAttachmentObjectTy
         if ($objectID) {
             $message = new ConversationMessage($objectID);
             $conversation = Conversation::getUserConversation($message->conversationID, WCF::getUser()->userID);
-            if ($conversation->canRead()) {
+            if ($conversation !== null && $conversation->canRead()) {
                 return true;
             }
         }
-- 
2.20.1