Remove redundant checks on room forgottenness

Fixes #3550

4 files changed, 2 insertions, 46 deletions

diff --git a/changelog.d/3350.misc b/changelog.d/3350.misc
new file mode 100644
index 0000000000..3713cd6d63
--- /dev/null
+++ b/changelog.d/3350.misc
@@ -0,0 +1 @@
+Remove redundant checks on who_forgot_in_room
\ No newline at end of file
diff --git a/synapse/storage/push_rule.py b/synapse/storage/push_rule.py
index be655d287b..d25b39ec02 100644
--- a/synapse/storage/push_rule.py
+++ b/synapse/storage/push_rule.py
@@ -21,7 +21,6 @@ from canonicaljson import json
 
 from twisted.internet import defer
 
-from synapse.api.constants import EventTypes
 from synapse.push.baserules import list_with_base_rules
 from synapse.storage.appservice import ApplicationServiceWorkerStore
 from synapse.storage.pusher import PusherWorkerStore
@@ -247,18 +246,6 @@ class PushRulesWorkerStore(ApplicationServiceWorkerStore,
             if uid in local_users_in_room:
                 user_ids.add(uid)
 
-        forgotten = yield self.who_forgot_in_room(
-            event.room_id, on_invalidate=cache_context.invalidate,
-        )
-
-        for row in forgotten:
-            user_id = row["user_id"]
-            event_id = row["event_id"]
-
-            mem_id = current_state_ids.get((EventTypes.Member, user_id), None)
-            if event_id == mem_id:
-                user_ids.discard(user_id)
-
         rules_by_user = yield self.bulk_get_push_rules(
             user_ids, on_invalidate=cache_context.invalidate,
         )
diff --git a/synapse/storage/roommember.py b/synapse/storage/roommember.py
index 02a802bed9..9eb5b18144 100644
--- a/synapse/storage/roommember.py
+++ b/synapse/storage/roommember.py
@@ -458,18 +458,6 @@ class RoomMemberWorkerStore(EventsWorkerStore):
     def _get_joined_hosts_cache(self, room_id):
         return _JoinedHostsCache(self, room_id)
 
-    @cached()
-    def who_forgot_in_room(self, room_id):
-        return self._simple_select_list(
-            table="room_memberships",
-            retcols=("user_id", "event_id"),
-            keyvalues={
-                "room_id": room_id,
-                "forgotten": 1,
-            },
-            desc="who_forgot"
-        )
-
 
 class RoomMemberStore(RoomMemberWorkerStore):
     def __init__(self, db_conn, hs):
@@ -578,9 +566,6 @@ class RoomMemberStore(RoomMemberWorkerStore):
             txn.execute(sql, (user_id, room_id))
 
             txn.call_after(self.did_forget.invalidate, (user_id, room_id))
-            self._invalidate_cache_and_stream(
-                txn, self.who_forgot_in_room, (room_id,)
-            )
         return self.runInteraction("forget_membership", f)
 
     @cachedInlineCallbacks(num_args=2)
diff --git a/synapse/visibility.py b/synapse/visibility.py
index 9b97ea2b83..e0b2eccceb 100644
--- a/synapse/visibility.py
+++ b/synapse/visibility.py
@@ -23,7 +23,6 @@ from twisted.internet import defer
 from synapse.api.constants import EventTypes, Membership
 from synapse.events.utils import prune_event
 from synapse.types import get_domain_from_id
-from synapse.util.logcontext import make_deferred_yieldable, preserve_fn
 
 logger = logging.getLogger(__name__)
 
@@ -75,19 +74,6 @@ def filter_events_for_client(store, user_id, events, is_peeking=False,
         types=types,
     )
 
-    forgotten = yield make_deferred_yieldable(defer.gatherResults([
-        defer.maybeDeferred(
-            preserve_fn(store.who_forgot_in_room),
-            room_id,
-        )
-        for room_id in frozenset(e.room_id for e in events)
-    ], consumeErrors=True))
-
-    # Set of membership event_ids that have been forgotten
-    event_id_forgotten = frozenset(
-        row["event_id"] for rows in forgotten for row in rows
-    )
-
     ignore_dict_content = yield store.get_global_account_data_by_type_for_user(
         "m.ignored_user_list", user_id,
     )
@@ -176,10 +162,7 @@ def filter_events_for_client(store, user_id, events, is_peeking=False,
         if membership is None:
             membership_event = state.get((EventTypes.Member, user_id), None)
             if membership_event:
-                # XXX why do we do this?
-                # https://github.com/matrix-org/synapse/issues/3350
-                if membership_event.event_id not in event_id_forgotten:
-                    membership = membership_event.membership
+                membership = membership_event.membership
 
         # if the user was a member of the room at the time of the event,
         # they can see it.