diff options
| -rw-r--r-- | changelog.d/14164.bugfix | 1 | ||||
| -rw-r--r-- | synapse/handlers/federation_event.py | 47 | ||||
| -rw-r--r-- | synapse/storage/databases/main/events_worker.py | 2 | ||||
| -rw-r--r-- | tests/handlers/test_federation.py | 105 |
4 files changed, 140 insertions, 15 deletions
diff --git a/changelog.d/14164.bugfix b/changelog.d/14164.bugfix new file mode 100644 index 0000000000..aed4d9e386 --- /dev/null +++ b/changelog.d/14164.bugfix @@ -0,0 +1 @@ +Fix a bug introduced in 1.30.0 where purging and rejoining a room without restarting in-between would result in a broken room. \ No newline at end of file diff --git a/synapse/handlers/federation_event.py b/synapse/handlers/federation_event.py index 4300e8dd40..06e41b5cc0 100644 --- a/synapse/handlers/federation_event.py +++ b/synapse/handlers/federation_event.py @@ -798,9 +798,42 @@ class FederationEventHandler: ], ) + # Check if we already any of these have these events. + # Note: we currently make a lookup in the database directly here rather than + # checking the event cache, due to: + # https://github.com/matrix-org/synapse/issues/13476 + existing_events_map = await self._store._get_events_from_db( + [event.event_id for event in events] + ) + + new_events = [] + for event in events: + event_id = event.event_id + + # If we've already seen this event ID... + if event_id in existing_events_map: + existing_event = existing_events_map[event_id] + + # ...and the event itself was not previously stored as an outlier... + if not existing_event.event.internal_metadata.is_outlier(): + # ...then there's no need to persist it. We have it already. + logger.info( + "_process_pulled_event: Ignoring received event %s which we " + "have already seen", + event.event_id, + ) + continue + + # While we have seen this event before, it was stored as an outlier. + # We'll now persist it as a non-outlier. + logger.info("De-outliering event %s", event_id) + + # Continue on with the events that are new to us. + new_events.append(event) + # We want to sort these by depth so we process them and # tell clients about them in order. - sorted_events = sorted(events, key=lambda x: x.depth) + sorted_events = sorted(new_events, key=lambda x: x.depth) for ev in sorted_events: with nested_logging_context(ev.event_id): await self._process_pulled_event(origin, ev, backfilled=backfilled) @@ -852,18 +885,6 @@ class FederationEventHandler: event_id = event.event_id - existing = await self._store.get_event( - event_id, allow_none=True, allow_rejected=True - ) - if existing: - if not existing.internal_metadata.is_outlier(): - logger.info( - "_process_pulled_event: Ignoring received event %s which we have already seen", - event_id, - ) - return - logger.info("De-outliering event %s", event_id) - try: self._sanity_check_event(event) except SynapseError as err: diff --git a/synapse/storage/databases/main/events_worker.py b/synapse/storage/databases/main/events_worker.py index cfd4780add..7bc7f2f33e 100644 --- a/synapse/storage/databases/main/events_worker.py +++ b/synapse/storage/databases/main/events_worker.py @@ -374,7 +374,7 @@ class EventsWorkerStore(SQLBaseStore): If there is a mismatch, behave as per allow_none. Returns: - The event, or None if the event was not found. + The event, or None if the event was not found and allow_none is `True`. """ if not isinstance(event_id, str): raise TypeError("Invalid event event_id %r" % (event_id,)) diff --git a/tests/handlers/test_federation.py b/tests/handlers/test_federation.py index 745750b1d7..d00c69c229 100644 --- a/tests/handlers/test_federation.py +++ b/tests/handlers/test_federation.py @@ -19,7 +19,13 @@ from unittest.mock import Mock, patch from twisted.test.proto_helpers import MemoryReactor from synapse.api.constants import EventTypes -from synapse.api.errors import AuthError, Codes, LimitExceededError, SynapseError +from synapse.api.errors import ( + AuthError, + Codes, + LimitExceededError, + NotFoundError, + SynapseError, +) from synapse.api.room_versions import RoomVersions from synapse.events import EventBase, make_event_from_dict from synapse.federation.federation_base import event_from_pdu_json @@ -28,6 +34,7 @@ from synapse.logging.context import LoggingContext, run_in_background from synapse.rest import admin from synapse.rest.client import login, room from synapse.server import HomeServer +from synapse.storage.databases.main.events_worker import EventCacheEntry from synapse.util import Clock from synapse.util.stringutils import random_string @@ -322,6 +329,102 @@ class FederationTestCase(unittest.FederatingHomeserverTestCase): ) self.get_success(d) + def test_backfill_ignores_known_events(self) -> None: + """ + Tests that events that we already know about are ignored when backfilling. + """ + # Set up users + user_id = self.register_user("kermit", "test") + tok = self.login("kermit", "test") + + other_server = "otherserver" + other_user = "@otheruser:" + other_server + + # Create a room to backfill events into + room_id = self.helper.create_room_as(room_creator=user_id, tok=tok) + room_version = self.get_success(self.store.get_room_version(room_id)) + + # Build an event to backfill + event = event_from_pdu_json( + { + "type": EventTypes.Message, + "content": {"body": "hello world", "msgtype": "m.text"}, + "room_id": room_id, + "sender": other_user, + "depth": 32, + "prev_events": [], + "auth_events": [], + "origin_server_ts": self.clock.time_msec(), + }, + room_version, + ) + + # Ensure the event is not already in the DB + self.get_failure( + self.store.get_event(event.event_id), + NotFoundError, + ) + + # Backfill the event and check that it has entered the DB. + + # We mock out the FederationClient.backfill method, to pretend that a remote + # server has returned our fake event. + federation_client_backfill_mock = Mock(return_value=make_awaitable([event])) + self.hs.get_federation_client().backfill = federation_client_backfill_mock + + # We also mock the persist method with a side effect of itself. This allows us + # to track when it has been called while preserving its function. + persist_events_and_notify_mock = Mock( + side_effect=self.hs.get_federation_event_handler().persist_events_and_notify + ) + self.hs.get_federation_event_handler().persist_events_and_notify = ( + persist_events_and_notify_mock + ) + + # Small side-tangent. We populate the event cache with the event, even though + # it is not yet in the DB. This is an invalid scenario that can currently occur + # due to not properly invalidating the event cache. + # See https://github.com/matrix-org/synapse/issues/13476. + # + # As a result, backfill should not rely on the event cache to check whether + # we already have an event in the DB. + # TODO: Remove this bit when the event cache is properly invalidated. + cache_entry = EventCacheEntry( + event=event, + redacted_event=None, + ) + self.store._get_event_cache.set_local((event.event_id,), cache_entry) + + # We now call FederationEventHandler.backfill (a separate method) to trigger + # a backfill request. It should receive the fake event. + self.get_success( + self.hs.get_federation_event_handler().backfill( + other_user, + room_id, + limit=10, + extremities=[], + ) + ) + + # Check that our fake event was persisted. + persist_events_and_notify_mock.assert_called_once() + persist_events_and_notify_mock.reset_mock() + + # Now we repeat the backfill, having the homeserver receive the fake event + # again. + self.get_success( + self.hs.get_federation_event_handler().backfill( + other_user, + room_id, + limit=10, + extremities=[], + ), + ) + + # This time, we expect no event persistence to have occurred, as we already + # have this event. + persist_events_and_notify_mock.assert_not_called() + @unittest.override_config( {"rc_invites": {"per_user": {"per_second": 0.5, "burst_count": 3}}} ) |