Fix SIGSEGV when a message sender is nil

telegram/utils.go

@@ -252,13 +252,15 @@ func (c *Client) formatMessage(chatID int64, messageID int64, preview bool, mess
 
 	var str strings.Builder
 	var senderId int64
-	switch message.SenderId.MessageSenderType() {
-	case client.TypeMessageSenderUser:
-		senderUser, _ := message.SenderId.(*client.MessageSenderUser)
-		senderId = senderUser.UserId
-	case client.TypeMessageSenderChat:
-		senderChat, _ := message.SenderId.(*client.MessageSenderChat)
-		senderId = senderChat.ChatId
+	if message.SenderId != nil {
+		switch message.SenderId.MessageSenderType() {
+		case client.TypeMessageSenderUser:
+			senderUser, _ := message.SenderId.(*client.MessageSenderUser)
+			senderId = senderUser.UserId
+		case client.TypeMessageSenderChat:
+			senderChat, _ := message.SenderId.(*client.MessageSenderChat)
+			senderId = senderChat.ChatId
+		}
 	}
 	str.WriteString(fmt.Sprintf("%v | %s | ", message.Id, c.formatContact(senderId)))
 	if !preview {