From 230b709d9d8b09fd4884be1265db535263975e35 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com> Date: Thu, 4 Apr 2024 13:14:24 +0100 Subject: [PATCH] `/sync`: fix bug in calculating `state` response (#16930) Fix a long-standing issue which could cause state to be omitted from the sync response if the last event was filtered out. Fixes: https://github.com/element-hq/synapse/issues/16928 --- changelog.d/16930.bugfix | 1 + synapse/handlers/sync.py | 54 ++++++------------------- tests/handlers/test_sync.py | 80 +++++++++++++++++++++++++++++++++++++ 3 files changed, 94 insertions(+), 41 deletions(-) create mode 100644 changelog.d/16930.bugfix diff --git a/changelog.d/16930.bugfix b/changelog.d/16930.bugfix new file mode 100644 index 0000000000..21f964ef97 --- /dev/null +++ b/changelog.d/16930.bugfix @@ -0,0 +1 @@ +Fix a long-standing bug which could cause state to be omitted from `/sync` responses when certain events are filtered out of the timeline. diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py index 7fcd54ac55..773e291aa8 100644 --- a/synapse/handlers/sync.py +++ b/synapse/handlers/sync.py @@ -1187,15 +1187,14 @@ class SyncHandler: await_full_state = True lazy_load_members = False - if batch: - state_at_timeline_end = ( - await self._state_storage_controller.get_state_ids_for_event( - batch.events[-1].event_id, - state_filter=state_filter, - await_full_state=await_full_state, - ) - ) + state_at_timeline_end = await self.get_state_at( + room_id, + stream_position=end_token, + state_filter=state_filter, + await_full_state=await_full_state, + ) + if batch: state_at_timeline_start = ( await self._state_storage_controller.get_state_ids_for_event( batch.events[0].event_id, @@ -1204,13 +1203,6 @@ class SyncHandler: ) ) else: - state_at_timeline_end = await self.get_state_at( - room_id, - stream_position=end_token, - state_filter=state_filter, - await_full_state=await_full_state, - ) - state_at_timeline_start = state_at_timeline_end state_ids = _calculate_state( @@ -1305,23 +1297,12 @@ class SyncHandler: await_full_state=await_full_state, ) - if batch: - state_at_timeline_end = ( - await self._state_storage_controller.get_state_ids_for_event( - batch.events[-1].event_id, - state_filter=state_filter, - await_full_state=await_full_state, - ) - ) - else: - # We can get here if the user has ignored the senders of all - # the recent events. - state_at_timeline_end = await self.get_state_at( - room_id, - stream_position=end_token, - state_filter=state_filter, - await_full_state=await_full_state, - ) + state_at_timeline_end = await self.get_state_at( + room_id, + stream_position=end_token, + state_filter=state_filter, + await_full_state=await_full_state, + ) state_ids = _calculate_state( timeline_contains=timeline_state, @@ -2847,15 +2828,6 @@ def _calculate_state( # timeline. We have no way to represent that in the /sync response, and we don't # even try; it is ether omitted or plonked into `state` as if it were at the start # of the timeline, depending on what else is in the timeline.) - # - # ---------- - # - # Aside 2: it's worth noting that `timeline_end`, as provided to us, is actually - # the state *before* the final event in the timeline. In other words: if the final - # event in the timeline is a state event, it won't be included in `timeline_end`. - # However, that doesn't matter here, because the only difference can be in that - # one piece of state, and by definition that event is in the timeline, so we - # don't need to include it in the `state` section. state_ids = ( (timeline_end_ids | timeline_start_ids) diff --git a/tests/handlers/test_sync.py b/tests/handlers/test_sync.py index 897c52c785..5d8e886541 100644 --- a/tests/handlers/test_sync.py +++ b/tests/handlers/test_sync.py @@ -355,6 +355,86 @@ class SyncTestCase(tests.unittest.HomeserverTestCase): [s2_event], ) + def test_state_includes_changes_on_forks_when_events_excluded(self) -> None: + """A variation on the previous test, but where one event is filtered + + The DAG is the same as the previous test, but E4 is excluded by the filter. + + E1 + ↗ ↖ + | S2 + | ↑ + --|------|---- + | | + E3 | + ↖ / + (E4) + + """ + + alice = self.register_user("alice", "password") + alice_tok = self.login(alice, "password") + alice_requester = create_requester(alice) + room_id = self.helper.create_room_as(alice, is_public=True, tok=alice_tok) + + # Do an initial sync as Alice to get a known starting point. + initial_sync_result = self.get_success( + self.sync_handler.wait_for_sync_for_user( + alice_requester, generate_sync_config(alice) + ) + ) + last_room_creation_event_id = ( + initial_sync_result.joined[0].timeline.events[-1].event_id + ) + + # Send a state event, and a regular event, both using the same prev ID + with self._patch_get_latest_events([last_room_creation_event_id]): + s2_event = self.helper.send_state(room_id, "s2", {}, tok=alice_tok)[ + "event_id" + ] + e3_event = self.helper.send(room_id, "e3", tok=alice_tok)["event_id"] + + # Send a final event, joining the two branches of the dag + self.helper.send(room_id, "e4", type="not_a_normal_message", tok=alice_tok)[ + "event_id" + ] + + # do an incremental sync, with a filter that will only return E3, excluding S2 + # and E4. + incremental_sync = self.get_success( + self.sync_handler.wait_for_sync_for_user( + alice_requester, + generate_sync_config( + alice, + filter_collection=FilterCollection( + self.hs, + { + "room": { + "timeline": { + "limit": 1, + "not_types": ["not_a_normal_message"], + } + } + }, + ), + ), + since_token=initial_sync_result.next_batch, + ) + ) + + # The state event should appear in the 'state' section of the response. + room_sync = incremental_sync.joined[0] + self.assertEqual(room_sync.room_id, room_id) + self.assertTrue(room_sync.timeline.limited) + self.assertEqual( + [e.event_id for e in room_sync.timeline.events], + [e3_event], + ) + self.assertEqual( + [e.event_id for e in room_sync.state.values()], + [s2_event], + ) + @parameterized.expand( [ (False, False),