From 1b732c76e65f1ef3d56203ad7ef814be3faead10 Mon Sep 17 00:00:00 2001
From: hide_d <hided62@gmail.com>
Date: Fri, 30 Nov 2018 21:49:19 +0900
Subject: [PATCH] =?UTF-8?q?=EA=B5=AD=EB=A9=94=20=EC=82=AD=EC=A0=9C=20?=
 =?UTF-8?q?=EA=B0=80=EB=8A=A5?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 hwe/sammo/Message.php | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/hwe/sammo/Message.php b/hwe/sammo/Message.php
index dfef9c98..d88a4445 100644
--- a/hwe/sammo/Message.php
+++ b/hwe/sammo/Message.php
@@ -289,11 +289,15 @@ class Message
         ];
 
         if($msgObj->msgType == Message::MSGTYPE_PRIVATE || $msgObj->msgType == Message::MSGTYPE_NATIONAL){
-            $msgObj2 = static::getMessageByID($msgObj->msgOption['receiverMessageID']);
-            if($msgObj2 !== null){
-                $msgObj2->invalidate(null, false);
-                $msgOption['overwrite'][] = [$msgObj2->id];
+            $receiveID = $msgObj->msgOption['receiverMessageID']??null;
+            if($receiveID !== null){
+                $msgObj2 = static::getMessageByID($receiveID);
+                if($msgObj2 !== null){
+                    $msgObj2->invalidate(null, false);
+                    $msgOption['overwrite'][] = [$msgObj2->id];
+                }
             }
+            
         }
 
         $in1min = new \DateTime();