Attempting to join rooms fails with a 500 #19233
Description
Description
when joining rooms on other homeservers, synapse will fail to join the room, giving a 500 error, and will show an error like this on the client:
the response has the following body: {"errcode":"M_UNKNOWN","error":"Internal server error"}
Steps to reproduce
- install synapse 1.143.0, setup the config to use postgresql and make it not leak memory
- try joining any room on another homeserver
- expect it to start joining the room or to timeout, but instead get a 500 error and the following logs
Homeserver
ineedmore.money, which I manage, and is running synapse 1.143.0
Synapse Version
1.143.0
Installation Method
Other (please mention below)
Database
a single PostgreSQL 17 server
Workers
Single process
Platform
this is running on an Alpine Linux edge system using the provided synapse package: https://pkgs.alpinelinux.org/package/edge/community/x86_64/synapse
Configuration
nothing unusual seems to be turned on and presence is disabled
Relevant log output
2025-11-26 21:51:19,678 - synapse.http.matrixfederationclient - 370 - INFO - POST-2539 - {PUT-O-797} [matrix.org] Completed request: 200 OK in 0.67 secs, got 35335 bytes - PUT matrix-federation://matrix.org/_matrix/federation/v2/send_join/%21aPQx8hPCm0vu6PiwsZbVSsVPlugBWOyanle4y5-8p7Q/%24kd1trFCoYmAwPiFo8REBPKXnJ84UMl11bgkd8V6Mk80?omit_members=true
2025-11-26 21:51:19,679 - synapse.federation.federation_client - 1228 - INFO - POST-2539 - Processing from send_join 19 events
2025-11-26 21:51:19,903 - synapse.handlers.federation - 1914 - INFO - sync_partial_state_room-9 - Syncing state for room !aPQx8hPCm0vu6PiwsZbVSsVPlugBWOyanle4y5-8p7Q via matrix.org
2025-11-26 21:51:19,905 - synapse.http.server - 146 - ERROR - POST-2539 - Failed handle request via 'JoinRoomAliasServlet': <XForwardedForRequest at 0x7c72c2d520c0 method='POST' uri='/_matrix/client/v3/join/!aPQx8hPCm0vu6PiwsZbVSsVPlugBWOyanle4y5-8p7Q?server_name=matrix.org&via=matrix.org' clientproto='HTTP/1.1' site='8008'>
Traceback (most recent call last):
File "/usr/lib/python3.12/site-packages/synapse/http/server.py", line 334, in _async_render_wrapper
callback_return = await self._async_render(request)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.12/site-packages/synapse/http/server.py", line 575, in _async_render
callback_return = await raw_callback_return
^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.12/site-packages/synapse/rest/client/room.py", line 583, in on_POST
return await self._do(request, requester, room_identifier, None)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.12/site-packages/synapse/rest/client/room.py", line 564, in _do
await self.room_member_handler.update_membership(
File "/usr/lib/python3.12/site-packages/synapse/handlers/room_member.py", line 662, in update_membership
result = await self.update_membership_locked(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.12/site-packages/synapse/handlers/room_member.py", line 1099, in update_membership_locked
remote_join_response = await self._remote_join(
^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.12/site-packages/synapse/handlers/room_member.py", line 1944, in _remote_join
event_id, stream_id = await self.federation_handler.do_invite_join(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.12/site-packages/synapse/handlers/federation.py", line 715, in do_invite_join
await self._federation_event_handler.process_remote_join(
File "/usr/lib/python3.12/site-packages/synapse/handlers/federation_event.py", line 568, in process_remote_join
await self._auth_and_persist_outliers(
File "/usr/lib/python3.12/site-packages/synapse/handlers/federation_event.py", line 1720, in _auth_and_persist_outliers
ev.event_id: [e_id for e_id in ev.auth_event_ids() if e_id in event_map]
^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.12/site-packages/synapse/events/__init__.py", line 551, in auth_event_ids
return self._dict["auth_events"] + [create_event_id]
~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~
TypeError: can only concatenate tuple (not "list") to tuple
2025-11-26 21:51:19,907 - synapse.handlers.federation - 1922 - INFO - sync_partial_state_room-9 - Updating current state for !aPQx8hPCm0vu6PiwsZbVSsVPlugBWOyanle4y5-8p7Q
2025-11-26 21:51:19,907 - synapse.access.http.8008 - 521 - INFO - POST-2539 - 2601:985:4c00:8690::28b5 - 8008 - {@jersey:ineedmore.money} Processed request: 1.303sec/0.001sec (0.022sec, 0.004sec) (0.042sec/0.076sec/32) 55B 500 "POST /_matrix/client/v3/join/!aPQx8hPCm0vu6PiwsZbVSsVPlugBWOyanle4y5-8p7Q?server_name=matrix.org&via=matrix.org HTTP/1.1" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36" [0 dbevts]
2025-11-26 21:51:19,910 - synapse.handlers.federation - 1932 - INFO - sync_partial_state_room-9 - Handling any pending device list updates
2025-11-26 21:51:19,913 - synapse.handlers.federation - 1936 - INFO - sync_partial_state_room-9 - Clearing partial-state flag for !aPQx8hPCm0vu6PiwsZbVSsVPlugBWOyanle4y5-8p7QAnything else that would be useful to know?
No response