Fix #1039: messages sent to Slack being synced back (#1046)

This is a regression from https://github.com/42wim/matterbridge/pull/581#issuecomment-562937576 Behaves the same as https://github.com/matterbridge/slack/commit/95190f11bfb6405b0394b75a29bd1c1bb91f553e
2020-03-21 19:12:30 +00:00
parent 6b017b226a
commit 0951e75c85
1 changed files with 2 additions and 1 deletions
@@ -498,7 +498,8 @@ func (b *Bslack) prepareMessageOptions(msg *config.Message) []slack.MsgOption {

 	var attachments []slack.Attachment
 	// add a callback ID so we can see we created it
-	attachments = append(attachments, slack.Attachment{CallbackID: "matterbridge_" + b.uuid})
+	const zeroWidthSpace = "\u200b"
+	attachments = append(attachments, slack.Attachment{CallbackID: "matterbridge_" + b.uuid, Fallback: zeroWidthSpace})
 	// add file attachments
 	attachments = append(attachments, b.createAttach(msg.Extra)...)
 	// add slack attachments (from another slack bridge)