New server notices do not create a new room after previous was exited

[dkasak]

Description

After receiving a server notice, if a user exits the notices room, he won't be
invited to a new room when a new notice happens. In fact, the new notice gets
lost / is never received by the user.

Steps to reproduce

1. Send server notice to a user via the _synapse/admin/v1/send_server_notice API.
2. Have the user accept the invite and then exit the room.
3. Send another server notice.

No new room is created for the new server notice from step 3 and it is
therefore never received.

Version information

• Homeserver: https://termina.org.uk
• Version: Synapse 1.2.1
• Install method: FreeBSD ports collection
• Platform: FreeBSD 11

[richvdh]

this surprises me. The server-notices code checks that the user is still a member of the room, and should create a new room if not.

[dkasak]

I just tried again and the bug is definitely there for me until I restart synapse. Then the user involved can receive notices again.