Requesting group user list fails with 500

[Half-Shot]

Description

Requested from half-shot.uk for the list of users in +polynomial-supporters:matrix.org. I got a 500 back and from inspecting matrix.org there seems to be a SynapseError: 500 - More than one row matched error.

Logs (from matrix.org)

2018-07-17 12:25:38,316 - synapse.access.http.8080 - 92 - INFO - GET-685693 - 212.129.29.2 - 8080 - Received request: GET /_matrix/federation/v1/groups/%2Bpolynomial-supporters%3Amatrix.org/users?requester_user_id=%40Half-Shot%3Ahalf-shot.uk
2018-07-17 12:25:38,317 - synapse.federation.transport.server - 130 - INFO - GET-685693 - Request from half-shot.uk
2018-07-17 12:25:59,240 - synapse.http.server - 83 - INFO - GET-685693 - <XForwardedForRequest at 0x7f0449b39e18 method='GET' uri='/_matrix/federation/v1/groups/%2Bpolynomial-supporters%3Amatrix.org/users?requester_user_id=%40Half-Shot%3Ahalf-shot.uk' clientproto='HTTP/1.1' site=8080> SynapseError: 500 - More than one row matched
2018-07-17 12:25:59,240 - synapse.access.http.8080 - 138 - INFO - GET-685693 - 212.129.29.2 - 8080 - {half-shot.uk} Processed request: 20.924sec (0.036sec, 0.004sec) (0.013sec/0.028sec/56) 59B 500 "GET /_matrix/federation/v1/groups/%2Bpolynomial-supporters%3Amatrix.org/users?requester_user_id=%40Half-Shot%3Ahalf-shot.uk HTTP/1.1" "Synapse/0.32.0" [0 dbevts]

Steps to reproduce

• Open a group page on Riot like https://riot.im/develop/#/group/+polynomial-supporters:matrix.org
  • Alternatively request GET https://example.com/_matrix/client/r0/groups/%2Bpolynomial-supporters%3Amatrix.org/users
• Wait a while
• Should come back with 500

[richvdh]

dup #2633