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.

1 files changed, 147 insertions, 0 deletions

diff --git a/tests/rest/client/test_read_marker.py b/tests/rest/client/test_read_marker.py
new file mode 100644
index 0000000000..0eedcdb476
--- /dev/null
+++ b/tests/rest/client/test_read_marker.py
@@ -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)