If we find ourselves dealing with rejected events, we proably want to know
about it. Let's include it in the stringification of the event so that it gets
logged.
Currently, when we receive an event whose auth_events differ from those we expect, we state-resolve between the two state sets, and check that the event passes auth based on the resolved state.
This means that it's possible for us to accept events which don't pass auth at their declared auth_events (or where the auth events themselves were rejected), leading to problems down the line like #10083.
This change means we will:
* ignore any events where we cannot find the auth events
* reject any events whose auth events were rejected
* reject any events which do not pass auth at their declared auth_events.
Together with a whole raft of previous work, this is a partial fix to #9595.
Fixes#6643.
Based on #11009.
This fixes a bug where we would accept an event whose `auth_events` include
rejected events, if the rejected event was shadowed by another `auth_event`
with same `(type, state_key)`.
The approach is to pass a list of auth events into
`check_auth_rules_for_event` instead of a dict, which of course means updating
the call sites.
This is an extension of #10956.
Instead of triggering `__exit__` manually on the replication handler's
logging context, use it as a context manager so that there is an
`__enter__` call to balance the `__exit__`.
Found while working on the Gitter backfill script and noticed
it only happened after we sent 7 batches, https://gitlab.com/gitterHQ/webapp/-/merge_requests/2229#note_665906390
When there are more than 5 backward extremities for a given depth,
backfill will throw an error because we sliced the extremity list
to 5 but then try to iterate over the full list. This causes
us to look for state that we never fetched and we get a `KeyError`.
Before when calling `/messages` when there are more than 5 backward extremities:
```
Traceback (most recent call last):
File "/usr/local/lib/python3.8/site-packages/synapse/http/server.py", line 258, in _async_render_wrapper
callback_return = await self._async_render(request)
File "/usr/local/lib/python3.8/site-packages/synapse/http/server.py", line 446, in _async_render
callback_return = await raw_callback_return
File "/usr/local/lib/python3.8/site-packages/synapse/rest/client/room.py", line 580, in on_GET
msgs = await self.pagination_handler.get_messages(
File "/usr/local/lib/python3.8/site-packages/synapse/handlers/pagination.py", line 396, in get_messages
await self.hs.get_federation_handler().maybe_backfill(
File "/usr/local/lib/python3.8/site-packages/synapse/handlers/federation.py", line 133, in maybe_backfill
return await self._maybe_backfill_inner(room_id, current_depth, limit)
File "/usr/local/lib/python3.8/site-packages/synapse/handlers/federation.py", line 386, in _maybe_backfill_inner
likely_extremeties_domains = get_domains_from_state(states[e_id])
KeyError: '$zpFflMEBtZdgcMQWTakaVItTLMjLFdKcRWUPHbbSZJl'
```
Resolve and share `state_groups` for all historical events in batch. This also helps for showing the appropriate avatar/displayname in Element and will work whenever `/messages` has one of the historical messages as the first message in the batch.
This does have the flaw where if you just insert a single historical event somewhere, it probably won't resolve the state correctly from `/messages` or `/context` since it will grab a non historical event above or below with resolved state which never included the historical state back then. For the same reasions, this also does not work in Element between the transition from actual messages to historical messages. In the Gitter case, this isn't really a problem since all of the historical messages are in one big lump at the beginning of the room.
For a future iteration, might be good to look at `/messages` and `/context` to additionally add the `state` for any historical messages in that batch.
---
How are the `state_groups` shared? To illustrate the `state_group` sharing, see this example:
**Before** (new `state_group` for every event 😬, very inefficient):
```
# Tests from https://github.com/matrix-org/complement/pull/206
$ COMPLEMENT_ALWAYS_PRINT_SERVER_LOGS=1 COMPLEMENT_DIR=../complement ./scripts-dev/complement.sh TestBackfillingHistory/parallel/should_resolve_member_state_events_for_historical_events
create_new_client_event m.room.member event=$_JXfwUDIWS6xKGG4SmZXjSFrizhARM7QblhATVWWUcA state_group=None
create_new_client_event org.matrix.msc2716.insertion event=$1ZBfmBKEjg94d-vGYymKrVYeghwBOuGJ3wubU1-I9y0 state_group=9
create_new_client_event org.matrix.msc2716.insertion event=$Mq2JvRetTyclPuozRI682SAjYp3GqRuPc8_cH5-ezPY state_group=10
create_new_client_event m.room.message event=$MfmY4rBQkxrIp8jVwVMTJ4PKnxSigpG9E2cn7S0AtTo state_group=11
create_new_client_event m.room.message event=$uYOv6V8wiF7xHwOMt-60d1AoOIbqLgrDLz6ZIQDdWUI state_group=12
create_new_client_event m.room.message event=$PAbkJRMxb0bX4A6av463faiAhxkE3FEObM1xB4D0UG4 state_group=13
create_new_client_event org.matrix.msc2716.batch event=$Oy_S7AWN7rJQe_MYwGPEy6RtbYklrI-tAhmfiLrCaKI state_group=14
```
**After** (all events in batch sharing `state_group=10`) (the base insertion event has `state_group=8` which matches the `prev_event` we're inserting next to):
```
# Tests from https://github.com/matrix-org/complement/pull/206
$ COMPLEMENT_ALWAYS_PRINT_SERVER_LOGS=1 COMPLEMENT_DIR=../complement ./scripts-dev/complement.sh TestBackfillingHistory/parallel/should_resolve_member_state_events_for_historical_events
create_new_client_event m.room.member event=$PWomJ8PwENYEYuVNoG30gqtybuQQSZ55eldBUSs0i0U state_group=None
create_new_client_event org.matrix.msc2716.insertion event=$e_mCU7Eah9ABF6nQU7lu4E1RxIWccNF05AKaTT5m3lw state_group=9
create_new_client_event org.matrix.msc2716.insertion event=$ui7A3_GdXIcJq0C8GpyrF8X7B3DTjMd_WGCjogax7xU state_group=10
create_new_client_event m.room.message event=$EnTIM5rEGVezQJiYl62uFBl6kJ7B-sMxWqe2D_4FX1I state_group=10
create_new_client_event m.room.message event=$LGx5jGONnBPuNhAuZqHeEoXChd9ryVkuTZatGisOPjk state_group=10
create_new_client_event m.room.message event=$wW0zwoN50lbLu1KoKbybVMxLbKUj7GV_olozIc5i3M0 state_group=10
create_new_client_event org.matrix.msc2716.batch event=$5ZB6dtzqFBCEuMRgpkU201Qhx3WtXZGTz_YgldL6JrQ state_group=10
```
* Pull out `_handle_room_membership_event`
* Discard excluded users early
* Rearrange logic so the change is membership is effectively switched over. See PR for rationale.
The following scenarios would halt the user directory updater:
- user joins room
- user leaves room
- user present in room which switches from private to public, or vice versa.
for two classes of users:
- appservice senders
- users missing from the user table.
If this happened, the user directory would be stuck, unable to make forward progress.
Exclude both cases from the user directory, so that we ignore them.
Co-authored-by: Eric Eastwood <erice@element.io>
Co-authored-by: reivilibre <oliverw@matrix.org>
Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>
Co-authored-by: Brendan Abolivier <babolivier@matrix.org>
