From b7272b73aa38dcb19c9b075514f963390358113d Mon Sep 17 00:00:00 2001 From: Patrick Cloke Date: Thu, 22 Sep 2022 08:47:49 -0400 Subject: [PATCH] Properly paginate forward in the /relations API. (#13840) This fixes a bug where the `/relations` API with `dir=f` would skip the first item of each page (except the first page), causing incomplete data to be returned to the client. --- changelog.d/13840.bugfix | 1 + synapse/storage/databases/main/relations.py | 38 +++++++++++++++------ synapse/storage/databases/main/stream.py | 6 ++-- tests/rest/client/test_relations.py | 29 +++++++++++++++- 4 files changed, 60 insertions(+), 14 deletions(-) create mode 100644 changelog.d/13840.bugfix diff --git a/changelog.d/13840.bugfix b/changelog.d/13840.bugfix new file mode 100644 index 0000000000..0f014439a8 --- /dev/null +++ b/changelog.d/13840.bugfix @@ -0,0 +1 @@ +Fix a bug introduced in Synapse v1.53.0 where the experimental implementation of [MSC3715](https://github.com/matrix-org/matrix-spec-proposals/pull/3715) would give incorrect results when paginating forward. diff --git a/synapse/storage/databases/main/relations.py b/synapse/storage/databases/main/relations.py index 7bd27790eb..898947af95 100644 --- a/synapse/storage/databases/main/relations.py +++ b/synapse/storage/databases/main/relations.py @@ -51,6 +51,8 @@ class _RelatedEvent: event_id: str # The sender of the related event. sender: str + topological_ordering: Optional[int] + stream_ordering: int class RelationsWorkerStore(SQLBaseStore): @@ -91,6 +93,9 @@ class RelationsWorkerStore(SQLBaseStore): # it. The `event_id` must match the `event.event_id`. assert event.event_id == event_id + # Ensure bad limits aren't being passed in. + assert limit >= 0 + where_clause = ["relates_to_id = ?", "room_id = ?"] where_args: List[Union[str, int]] = [event.event_id, room_id] is_redacted = event.internal_metadata.is_redacted() @@ -139,21 +144,34 @@ class RelationsWorkerStore(SQLBaseStore): ) -> Tuple[List[_RelatedEvent], Optional[StreamToken]]: txn.execute(sql, where_args + [limit + 1]) - last_topo_id = None - last_stream_id = None events = [] - for row in txn: + for event_id, relation_type, sender, topo_ordering, stream_ordering in txn: # Do not include edits for redacted events as they leak event # content. - if not is_redacted or row[1] != RelationTypes.REPLACE: - events.append(_RelatedEvent(row[0], row[2])) - last_topo_id = row[3] - last_stream_id = row[4] + if not is_redacted or relation_type != RelationTypes.REPLACE: + events.append( + _RelatedEvent(event_id, sender, topo_ordering, stream_ordering) + ) - # If there are more events, generate the next pagination key. + # If there are more events, generate the next pagination key from the + # last event returned. next_token = None - if len(events) > limit and last_topo_id and last_stream_id: - next_key = RoomStreamToken(last_topo_id, last_stream_id) + if len(events) > limit: + # Instead of using the last row (which tells us there is more + # data), use the last row to be returned. + events = events[:limit] + + topo = events[-1].topological_ordering + token = events[-1].stream_ordering + if direction == "b": + # Tokens are positions between events. + # This token points *after* the last event in the chunk. + # We need it to point to the event before it in the chunk + # when we are going backwards so we subtract one from the + # stream part. + token -= 1 + next_key = RoomStreamToken(topo, token) + if from_token: next_token = from_token.copy_and_replace( StreamKeyType.ROOM, next_key diff --git a/synapse/storage/databases/main/stream.py b/synapse/storage/databases/main/stream.py index 3f9bfaeac5..530f04e149 100644 --- a/synapse/storage/databases/main/stream.py +++ b/synapse/storage/databases/main/stream.py @@ -1334,15 +1334,15 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): if rows: topo = rows[-1].topological_ordering - toke = rows[-1].stream_ordering + token = rows[-1].stream_ordering if direction == "b": # Tokens are positions between events. # This token points *after* the last event in the chunk. # We need it to point to the event before it in the chunk # when we are going backwards so we subtract one from the # stream part. - toke -= 1 - next_token = RoomStreamToken(topo, toke) + token -= 1 + next_token = RoomStreamToken(topo, token) else: # TODO (erikj): We should work out what to do here instead. next_token = to_token if to_token else from_token diff --git a/tests/rest/client/test_relations.py b/tests/rest/client/test_relations.py index 651f4f415d..d33e34d829 100644 --- a/tests/rest/client/test_relations.py +++ b/tests/rest/client/test_relations.py @@ -788,6 +788,7 @@ class RelationPaginationTestCase(BaseRelationsTestCase): channel.json_body["chunk"][0], ) + @unittest.override_config({"experimental_features": {"msc3715_enabled": True}}) def test_repeated_paginate_relations(self) -> None: """Test that if we paginate using a limit and tokens then we get the expected events. @@ -809,7 +810,7 @@ class RelationPaginationTestCase(BaseRelationsTestCase): channel = self.make_request( "GET", - f"/_matrix/client/v1/rooms/{self.room}/relations/{self.parent_id}?limit=1{from_token}", + f"/_matrix/client/v1/rooms/{self.room}/relations/{self.parent_id}?limit=3{from_token}", access_token=self.user_token, ) self.assertEqual(200, channel.code, channel.json_body) @@ -827,6 +828,32 @@ class RelationPaginationTestCase(BaseRelationsTestCase): found_event_ids.reverse() self.assertEqual(found_event_ids, expected_event_ids) + # Test forward pagination. + prev_token = "" + found_event_ids = [] + for _ in range(20): + from_token = "" + if prev_token: + from_token = "&from=" + prev_token + + channel = self.make_request( + "GET", + f"/_matrix/client/v1/rooms/{self.room}/relations/{self.parent_id}?org.matrix.msc3715.dir=f&limit=3{from_token}", + access_token=self.user_token, + ) + self.assertEqual(200, channel.code, channel.json_body) + + found_event_ids.extend(e["event_id"] for e in channel.json_body["chunk"]) + next_batch = channel.json_body.get("next_batch") + + self.assertNotEqual(prev_token, next_batch) + prev_token = next_batch + + if not prev_token: + break + + self.assertEqual(found_event_ids, expected_event_ids) + def test_pagination_from_sync_and_messages(self) -> None: """Pagination tokens from /sync and /messages can be used to paginate /relations.""" channel = self._send_relation(RelationTypes.ANNOTATION, "m.reaction", "A")