Also check if first event matches the last in prev batch (#17066)

Refinement of #17064 

cc @richvdh
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Erik Johnston 2024-04-09 15:01:12 +01:00 committed by GitHub
parent 4ffed6330f
commit 89f1092284
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3 changed files with 109 additions and 7 deletions

1
changelog.d/17066.bugfix Normal file
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@ -0,0 +1 @@
Fix various long-standing bugs which could cause incorrect state to be returned from `/sync` in certain situations.

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@ -1266,17 +1266,23 @@ class SyncHandler:
#
# c.f. #16941 for an example of why we can't do this for all non-gappy
# syncs.
is_linear_timeline = False
is_linear_timeline = True
if batch.events:
prev_event_id = batch.events[0].event_id
for e in batch.events[1:]:
# We need to make sure the first event in our batch points to the
# last event in the previous batch.
last_event_id_prev_batch = (
await self.store.get_last_event_in_room_before_stream_ordering(
room_id,
end_token=since_token.room_key,
)
)
prev_event_id = last_event_id_prev_batch
for e in batch.events:
if e.prev_event_ids() != [prev_event_id]:
is_linear_timeline = False
break
prev_event_id = e.event_id
else:
is_linear_timeline = True
else:
is_linear_timeline = True
if is_linear_timeline and not batch.limited:
state_ids: StateMap[str] = {}

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@ -435,6 +435,101 @@ class SyncTestCase(tests.unittest.HomeserverTestCase):
[s2_event],
)
def test_state_includes_changes_on_long_lived_forks(self) -> None:
"""State changes that happen on a fork of the DAG must be included in `state`
Given the following DAG:
E1
| S2
|
--|------|----
E3 |
--|------|----
| E4
| |
... and a filter that means we only return 1 event, represented by the dashed
horizontal lines: `S2` must be included in the `state` section on the second sync.
"""
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"]
# Do an incremental sync, this will return E3 but *not* S2 at this
# point.
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}}}
),
),
since_token=initial_sync_result.next_batch,
)
)
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()],
[],
)
# Now send another event that points to S2, but not E3.
with self._patch_get_latest_events([s2_event]):
e4_event = self.helper.send(room_id, "e4", tok=alice_tok)["event_id"]
# Doing an incremental sync should return S2 in state.
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}}}
),
),
since_token=incremental_sync.next_batch,
)
)
room_sync = incremental_sync.joined[0]
self.assertEqual(room_sync.room_id, room_id)
self.assertFalse(room_sync.timeline.limited)
self.assertEqual(
[e.event_id for e in room_sync.timeline.events],
[e4_event],
)
self.assertEqual(
[e.event_id for e in room_sync.state.values()],
[s2_event],
)
def test_state_includes_changes_on_ungappy_syncs(self) -> None:
"""Test `state` where the sync is not gappy.