No check before inviting user(s) to a community they are already member to

[Zeklandia]

Description

Unlike when inviting users to a room, there is no check to make sure the user(s) being invited are not already members of the community they are being invited to. This results in users being both a member and invited at the same time. If they decline this second invitation, it will remove them from the community.

Steps to reproduce

• Invite user to a community
• Have user join the community
• Invite the same user to the same community

Describe how what happens differs from what you expected.

I expected to receive a warning that the user(s) I tried to invite were already members of the community so their invitations couldn't be sent, like what happens with the same situation in rooms.

Logs being sent: no

Version information

• Platform: desktop

For the desktop app:

• OS: Windows
• Version: 1.3.2

[Zeklandia]

The underlying issue of double invitations and being kicked out upon declining a duplicate invitation are platform issues, but I do not know where in the pipeline that problem arises, so I am not sure where to report that.

[turt2live]

Closing in favour of the server-side bug: matrix-org/synapse#2633