Handle missing previous read marker event. (#15464)

If the previous read marker is pointing to an event that no longer exists
(e.g. due to retention) then assume that the newly given read marker
is newer.
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Nick Mills-Barrett 2023-05-18 19:37:31 +01:00 committed by GitHub
parent e5b4d93770
commit ad50510a06
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4 changed files with 162 additions and 10 deletions

1
changelog.d/15464.bugfix Normal file
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@ -0,0 +1 @@
Fix a long-standing bug where setting the read marker could fail when using message retention. Contributed by Nick @ Beeper (@fizzadar).

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@ -16,6 +16,7 @@ import logging
from typing import TYPE_CHECKING
from synapse.api.constants import ReceiptTypes
from synapse.api.errors import SynapseError
from synapse.util.async_helpers import Linearizer
if TYPE_CHECKING:
@ -47,12 +48,21 @@ class ReadMarkerHandler:
)
should_update = True
# Get event ordering, this also ensures we know about the event
event_ordering = await self.store.get_event_ordering(event_id)
if existing_read_marker:
# Only update if the new marker is ahead in the stream
should_update = await self.store.is_event_after(
event_id, existing_read_marker["event_id"]
)
try:
old_event_ordering = await self.store.get_event_ordering(
existing_read_marker["event_id"]
)
except SynapseError:
# Old event no longer exists, assume new is ahead. This may
# happen if the old event was removed due to retention.
pass
else:
# Only update if the new marker is ahead in the stream
should_update = event_ordering > old_event_ordering
if should_update:
content = {"event_id": event_id}

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@ -1973,12 +1973,6 @@ class EventsWorkerStore(SQLBaseStore):
return rows, to_token, True
async def is_event_after(self, event_id1: str, event_id2: str) -> bool:
"""Returns True if event_id1 is after event_id2 in the stream"""
to_1, so_1 = await self.get_event_ordering(event_id1)
to_2, so_2 = await self.get_event_ordering(event_id2)
return (to_1, so_1) > (to_2, so_2)
@cached(max_entries=5000)
async def get_event_ordering(self, event_id: str) -> Tuple[int, int]:
res = await self.db_pool.simple_select_one(

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@ -0,0 +1,147 @@
# Copyright 2023 Beeper
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from twisted.test.proto_helpers import MemoryReactor
import synapse.rest.admin
from synapse.api.constants import EventTypes
from synapse.rest import admin
from synapse.rest.client import login, read_marker, register, room
from synapse.server import HomeServer
from synapse.util import Clock
from tests import unittest
ONE_HOUR_MS = 3600000
ONE_DAY_MS = ONE_HOUR_MS * 24
class ReadMarkerTestCase(unittest.HomeserverTestCase):
servlets = [
login.register_servlets,
register.register_servlets,
read_marker.register_servlets,
room.register_servlets,
synapse.rest.admin.register_servlets,
admin.register_servlets,
]
def make_homeserver(self, reactor: MemoryReactor, clock: Clock) -> HomeServer:
config = self.default_config()
# merge this default retention config with anything that was specified in
# @override_config
retention_config = {
"enabled": True,
"allowed_lifetime_min": ONE_DAY_MS,
"allowed_lifetime_max": ONE_DAY_MS * 3,
}
retention_config.update(config.get("retention", {}))
config["retention"] = retention_config
self.hs = self.setup_test_homeserver(config=config)
return self.hs
def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
self.owner = self.register_user("owner", "pass")
self.owner_tok = self.login("owner", "pass")
self.store = self.hs.get_datastores().main
self.clock = self.hs.get_clock()
def test_send_read_marker(self) -> None:
room_id = self.helper.create_room_as(self.owner, tok=self.owner_tok)
def send_message() -> str:
res = self.helper.send(room_id=room_id, body="1", tok=self.owner_tok)
return res["event_id"]
# Test setting the read marker on the room
event_id_1 = send_message()
channel = self.make_request(
"POST",
"/rooms/!abc:beep/read_markers",
content={
"m.fully_read": event_id_1,
},
access_token=self.owner_tok,
)
self.assertEqual(channel.code, 200, channel.result)
# Test moving the read marker to a newer event
event_id_2 = send_message()
channel = self.make_request(
"POST",
"/rooms/!abc:beep/read_markers",
content={
"m.fully_read": event_id_2,
},
access_token=self.owner_tok,
)
self.assertEqual(channel.code, 200, channel.result)
def test_send_read_marker_missing_previous_event(self) -> None:
"""
Test moving a read marker from an event that previously existed but was
later removed due to retention rules.
"""
room_id = self.helper.create_room_as(self.owner, tok=self.owner_tok)
# Set retention rule on the room so we remove old events to test this case
self.helper.send_state(
room_id=room_id,
event_type=EventTypes.Retention,
body={"max_lifetime": ONE_DAY_MS},
tok=self.owner_tok,
)
def send_message() -> str:
res = self.helper.send(room_id=room_id, body="1", tok=self.owner_tok)
return res["event_id"]
# Test setting the read marker on the room
event_id_1 = send_message()
channel = self.make_request(
"POST",
"/rooms/!abc:beep/read_markers",
content={
"m.fully_read": event_id_1,
},
access_token=self.owner_tok,
)
# Send a second message (retention will not remove the latest event ever)
send_message()
# And then advance so retention rules remove the first event (where the marker is)
self.reactor.advance(ONE_DAY_MS * 2 / 1000)
event = self.get_success(self.store.get_event(event_id_1, allow_none=True))
assert event is None
# TODO See https://github.com/matrix-org/synapse/issues/13476
self.store.get_event_ordering.invalidate_all()
# Test moving the read marker to a newer event
event_id_2 = send_message()
channel = self.make_request(
"POST",
"/rooms/!abc:beep/read_markers",
content={
"m.fully_read": event_id_2,
},
access_token=self.owner_tok,
)
self.assertEqual(channel.code, 200, channel.result)