Clarify list/set/dict/tuple comprehensions and enforce via flake8 (#6957)

Ensure good comprehension hygiene using flake8-comprehensions.

1 files changed, 9 insertions, 9 deletions

diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index eb20ef4aec..a689065f89 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -659,11 +659,11 @@ class FederationHandler(BaseHandler):
         # this can happen if a remote server claims that the state or
         # auth_events at an event in room A are actually events in room B
 
-        bad_events = list(
+        bad_events = [
             (event_id, event.room_id)
             for event_id, event in fetched_events.items()
             if event.room_id != room_id
-        )
+        ]
 
         for bad_event_id, bad_room_id in bad_events:
             # This is a bogus situation, but since we may only discover it a long time
@@ -856,7 +856,7 @@ class FederationHandler(BaseHandler):
 
         # Don't bother processing events we already have.
         seen_events = await self.store.have_events_in_timeline(
-            set(e.event_id for e in events)
+            {e.event_id for e in events}
         )
 
         events = [e for e in events if e.event_id not in seen_events]
@@ -866,7 +866,7 @@ class FederationHandler(BaseHandler):
 
         event_map = {e.event_id: e for e in events}
 
-        event_ids = set(e.event_id for e in events)
+        event_ids = {e.event_id for e in events}
 
         # build a list of events whose prev_events weren't in the batch.
         # (XXX: this will include events whose prev_events we already have; that doesn't
@@ -892,13 +892,13 @@ class FederationHandler(BaseHandler):
             state_events.update({s.event_id: s for s in state})
             events_to_state[e_id] = state
 
-        required_auth = set(
+        required_auth = {
             a_id
             for event in events
             + list(state_events.values())
             + list(auth_events.values())
             for a_id in event.auth_event_ids()
-        )
+        }
         auth_events.update(
             {e_id: event_map[e_id] for e_id in required_auth if e_id in event_map}
         )
@@ -1247,7 +1247,7 @@ class FederationHandler(BaseHandler):
     async def on_event_auth(self, event_id: str) -> List[EventBase]:
         event = await self.store.get_event(event_id)
         auth = await self.store.get_auth_chain(
-            [auth_id for auth_id in event.auth_event_ids()], include_given=True
+            list(event.auth_event_ids()), include_given=True
         )
         return list(auth)
 
@@ -2152,7 +2152,7 @@ class FederationHandler(BaseHandler):
 
         # Now get the current auth_chain for the event.
         local_auth_chain = await self.store.get_auth_chain(
-            [auth_id for auth_id in event.auth_event_ids()], include_given=True
+            list(event.auth_event_ids()), include_given=True
         )
 
         # TODO: Check if we would now reject event_id. If so we need to tell
@@ -2654,7 +2654,7 @@ class FederationHandler(BaseHandler):
             member_handler = self.hs.get_room_member_handler()
             yield member_handler.send_membership_event(None, event, context)
         else:
-            destinations = set(x.split(":", 1)[-1] for x in (sender_user_id, room_id))
+            destinations = {x.split(":", 1)[-1] for x in (sender_user_id, room_id)}
             yield self.federation_client.forward_third_party_invite(
                 destinations, room_id, event_dict
             )