Replace returnValue with return (#5736)

39 files changed, 270 insertions, 288 deletions

diff --git a/synapse/rest/admin/__init__.py b/synapse/rest/admin/__init__.py
index 6888ae5590..0a7d9b81b2 100644
--- a/synapse/rest/admin/__init__.py
+++ b/synapse/rest/admin/__init__.py
@@ -84,7 +84,7 @@ class UsersRestServlet(RestServlet):
 
         ret = yield self.handlers.admin_handler.get_users()
 
-        defer.returnValue((200, ret))
+        return (200, ret)
 
 
 class VersionServlet(RestServlet):
@@ -227,7 +227,7 @@ class UserRegisterServlet(RestServlet):
         )
 
         result = yield register._create_registration_details(user_id, body)
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class WhoisRestServlet(RestServlet):
@@ -252,7 +252,7 @@ class WhoisRestServlet(RestServlet):
 
         ret = yield self.handlers.admin_handler.get_whois(target_user)
 
-        defer.returnValue((200, ret))
+        return (200, ret)
 
 
 class PurgeMediaCacheRestServlet(RestServlet):
@@ -271,7 +271,7 @@ class PurgeMediaCacheRestServlet(RestServlet):
 
         ret = yield self.media_repository.delete_old_remote_media(before_ts)
 
-        defer.returnValue((200, ret))
+        return (200, ret)
 
 
 class PurgeHistoryRestServlet(RestServlet):
@@ -356,7 +356,7 @@ class PurgeHistoryRestServlet(RestServlet):
             room_id, token, delete_local_events=delete_local_events
         )
 
-        defer.returnValue((200, {"purge_id": purge_id}))
+        return (200, {"purge_id": purge_id})
 
 
 class PurgeHistoryStatusRestServlet(RestServlet):
@@ -381,7 +381,7 @@ class PurgeHistoryStatusRestServlet(RestServlet):
         if purge_status is None:
             raise NotFoundError("purge id '%s' not found" % purge_id)
 
-        defer.returnValue((200, purge_status.asdict()))
+        return (200, purge_status.asdict())
 
 
 class DeactivateAccountRestServlet(RestServlet):
@@ -413,7 +413,7 @@ class DeactivateAccountRestServlet(RestServlet):
         else:
             id_server_unbind_result = "no-support"
 
-        defer.returnValue((200, {"id_server_unbind_result": id_server_unbind_result}))
+        return (200, {"id_server_unbind_result": id_server_unbind_result})
 
 
 class ShutdownRoomRestServlet(RestServlet):
@@ -531,16 +531,14 @@ class ShutdownRoomRestServlet(RestServlet):
             room_id, new_room_id, requester_user_id
         )
 
-        defer.returnValue(
-            (
-                200,
-                {
-                    "kicked_users": kicked_users,
-                    "failed_to_kick_users": failed_to_kick_users,
-                    "local_aliases": aliases_for_room,
-                    "new_room_id": new_room_id,
-                },
-            )
+        return (
+            200,
+            {
+                "kicked_users": kicked_users,
+                "failed_to_kick_users": failed_to_kick_users,
+                "local_aliases": aliases_for_room,
+                "new_room_id": new_room_id,
+            },
         )
 
 
@@ -564,7 +562,7 @@ class QuarantineMediaInRoom(RestServlet):
             room_id, requester.user.to_string()
         )
 
-        defer.returnValue((200, {"num_quarantined": num_quarantined}))
+        return (200, {"num_quarantined": num_quarantined})
 
 
 class ListMediaInRoom(RestServlet):
@@ -585,7 +583,7 @@ class ListMediaInRoom(RestServlet):
 
         local_mxcs, remote_mxcs = yield self.store.get_media_mxcs_in_room(room_id)
 
-        defer.returnValue((200, {"local": local_mxcs, "remote": remote_mxcs}))
+        return (200, {"local": local_mxcs, "remote": remote_mxcs})
 
 
 class ResetPasswordRestServlet(RestServlet):
@@ -629,7 +627,7 @@ class ResetPasswordRestServlet(RestServlet):
         yield self._set_password_handler.set_password(
             target_user_id, new_password, requester
         )
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 class GetUsersPaginatedRestServlet(RestServlet):
@@ -671,7 +669,7 @@ class GetUsersPaginatedRestServlet(RestServlet):
         logger.info("limit: %s, start: %s", limit, start)
 
         ret = yield self.handlers.admin_handler.get_users_paginate(order, start, limit)
-        defer.returnValue((200, ret))
+        return (200, ret)
 
     @defer.inlineCallbacks
     def on_POST(self, request, target_user_id):
@@ -699,7 +697,7 @@ class GetUsersPaginatedRestServlet(RestServlet):
         logger.info("limit: %s, start: %s", limit, start)
 
         ret = yield self.handlers.admin_handler.get_users_paginate(order, start, limit)
-        defer.returnValue((200, ret))
+        return (200, ret)
 
 
 class SearchUsersRestServlet(RestServlet):
@@ -742,7 +740,7 @@ class SearchUsersRestServlet(RestServlet):
         logger.info("term: %s ", term)
 
         ret = yield self.handlers.admin_handler.search_users(term)
-        defer.returnValue((200, ret))
+        return (200, ret)
 
 
 class DeleteGroupAdminRestServlet(RestServlet):
@@ -765,7 +763,7 @@ class DeleteGroupAdminRestServlet(RestServlet):
             raise SynapseError(400, "Can only delete local groups")
 
         yield self.group_server.delete_group(group_id, requester.user.to_string())
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 class AccountValidityRenewServlet(RestServlet):
@@ -796,7 +794,7 @@ class AccountValidityRenewServlet(RestServlet):
         )
 
         res = {"expiration_ts": expiration_ts}
-        defer.returnValue((200, res))
+        return (200, res)
 
 
 ########################################################################################
diff --git a/synapse/rest/admin/server_notice_servlet.py b/synapse/rest/admin/server_notice_servlet.py
index ee66838a0d..90c0ee15dc 100644
--- a/synapse/rest/admin/server_notice_servlet.py
+++ b/synapse/rest/admin/server_notice_servlet.py
@@ -87,7 +87,7 @@ class SendServerNoticeServlet(RestServlet):
             event_content=body["content"],
         )
 
-        defer.returnValue((200, {"event_id": event.event_id}))
+        return (200, {"event_id": event.event_id})
 
     def on_PUT(self, request, txn_id):
         return self.txns.fetch_or_execute_request(
diff --git a/synapse/rest/client/v1/directory.py b/synapse/rest/client/v1/directory.py
index 57542c2b4b..4284738021 100644
--- a/synapse/rest/client/v1/directory.py
+++ b/synapse/rest/client/v1/directory.py
@@ -54,7 +54,7 @@ class ClientDirectoryServer(RestServlet):
         dir_handler = self.handlers.directory_handler
         res = yield dir_handler.get_association(room_alias)
 
-        defer.returnValue((200, res))
+        return (200, res)
 
     @defer.inlineCallbacks
     def on_PUT(self, request, room_alias):
@@ -87,7 +87,7 @@ class ClientDirectoryServer(RestServlet):
             requester, room_alias, room_id, servers
         )
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, room_alias):
@@ -102,7 +102,7 @@ class ClientDirectoryServer(RestServlet):
                 service.url,
                 room_alias.to_string(),
             )
-            defer.returnValue((200, {}))
+            return (200, {})
         except InvalidClientCredentialsError:
             # fallback to default user behaviour if they aren't an AS
             pass
@@ -118,7 +118,7 @@ class ClientDirectoryServer(RestServlet):
             "User %s deleted alias %s", user.to_string(), room_alias.to_string()
         )
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 class ClientDirectoryListServer(RestServlet):
@@ -136,9 +136,7 @@ class ClientDirectoryListServer(RestServlet):
         if room is None:
             raise NotFoundError("Unknown room")
 
-        defer.returnValue(
-            (200, {"visibility": "public" if room["is_public"] else "private"})
-        )
+        return (200, {"visibility": "public" if room["is_public"] else "private"})
 
     @defer.inlineCallbacks
     def on_PUT(self, request, room_id):
@@ -151,7 +149,7 @@ class ClientDirectoryListServer(RestServlet):
             requester, room_id, visibility
         )
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, room_id):
@@ -161,7 +159,7 @@ class ClientDirectoryListServer(RestServlet):
             requester, room_id, "private"
         )
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 class ClientAppserviceDirectoryListServer(RestServlet):
@@ -195,4 +193,4 @@ class ClientAppserviceDirectoryListServer(RestServlet):
             requester.app_service.id, network_id, room_id, visibility
         )
 
-        defer.returnValue((200, {}))
+        return (200, {})
diff --git a/synapse/rest/client/v1/events.py b/synapse/rest/client/v1/events.py
index d6de2b7360..53ebed2203 100644
--- a/synapse/rest/client/v1/events.py
+++ b/synapse/rest/client/v1/events.py
@@ -67,7 +67,7 @@ class EventStreamRestServlet(RestServlet):
             is_guest=is_guest,
         )
 
-        defer.returnValue((200, chunk))
+        return (200, chunk)
 
     def on_OPTIONS(self, request):
         return (200, {})
@@ -91,9 +91,9 @@ class EventRestServlet(RestServlet):
         time_now = self.clock.time_msec()
         if event:
             event = yield self._event_serializer.serialize_event(event, time_now)
-            defer.returnValue((200, event))
+            return (200, event)
         else:
-            defer.returnValue((404, "Event not found."))
+            return (404, "Event not found.")
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v1/initial_sync.py b/synapse/rest/client/v1/initial_sync.py
index 0fe5f2d79b..70b8478e90 100644
--- a/synapse/rest/client/v1/initial_sync.py
+++ b/synapse/rest/client/v1/initial_sync.py
@@ -42,7 +42,7 @@ class InitialSyncRestServlet(RestServlet):
             include_archived=include_archived,
         )
 
-        defer.returnValue((200, content))
+        return (200, content)
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v1/login.py b/synapse/rest/client/v1/login.py
index 0d05945f0a..5762b9fd06 100644
--- a/synapse/rest/client/v1/login.py
+++ b/synapse/rest/client/v1/login.py
@@ -152,7 +152,7 @@ class LoginRestServlet(RestServlet):
         well_known_data = self._well_known_builder.get_well_known()
         if well_known_data:
             result["well_known"] = well_known_data
-        defer.returnValue((200, result))
+        return (200, result)
 
     @defer.inlineCallbacks
     def _do_other_login(self, login_submission):
@@ -212,7 +212,7 @@ class LoginRestServlet(RestServlet):
                 result = yield self._register_device_with_callback(
                     canonical_user_id, login_submission, callback_3pid
                 )
-                defer.returnValue(result)
+                return result
 
             # No password providers were able to handle this 3pid
             # Check local store
@@ -241,7 +241,7 @@ class LoginRestServlet(RestServlet):
         result = yield self._register_device_with_callback(
             canonical_user_id, login_submission, callback
         )
-        defer.returnValue(result)
+        return result
 
     @defer.inlineCallbacks
     def _register_device_with_callback(self, user_id, login_submission, callback=None):
@@ -273,7 +273,7 @@ class LoginRestServlet(RestServlet):
         if callback is not None:
             yield callback(result)
 
-        defer.returnValue(result)
+        return result
 
     @defer.inlineCallbacks
     def do_token_login(self, login_submission):
@@ -284,7 +284,7 @@ class LoginRestServlet(RestServlet):
         )
 
         result = yield self._register_device_with_callback(user_id, login_submission)
-        defer.returnValue(result)
+        return result
 
     @defer.inlineCallbacks
     def do_jwt_login(self, login_submission):
@@ -321,7 +321,7 @@ class LoginRestServlet(RestServlet):
         result = yield self._register_device_with_callback(
             registered_user_id, login_submission
         )
-        defer.returnValue(result)
+        return result
 
 
 class BaseSSORedirectServlet(RestServlet):
@@ -395,7 +395,7 @@ class CasTicketServlet(RestServlet):
             # even if that's being used old-http style to signal end-of-data
             body = pde.response
         result = yield self.handle_cas_response(request, body, client_redirect_url)
-        defer.returnValue(result)
+        return result
 
     def handle_cas_response(self, request, cas_response_body, client_redirect_url):
         user, attributes = self.parse_cas_response(cas_response_body)
diff --git a/synapse/rest/client/v1/logout.py b/synapse/rest/client/v1/logout.py
index cd711be519..2769f3a189 100644
--- a/synapse/rest/client/v1/logout.py
+++ b/synapse/rest/client/v1/logout.py
@@ -49,7 +49,7 @@ class LogoutRestServlet(RestServlet):
                 requester.user.to_string(), requester.device_id
             )
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 class LogoutAllRestServlet(RestServlet):
@@ -75,7 +75,7 @@ class LogoutAllRestServlet(RestServlet):
         # .. and then delete any access tokens which weren't associated with
         # devices.
         yield self._auth_handler.delete_access_tokens_for_user(user_id)
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v1/presence.py b/synapse/rest/client/v1/presence.py
index 3e87f0fdb3..1eb1068c98 100644
--- a/synapse/rest/client/v1/presence.py
+++ b/synapse/rest/client/v1/presence.py
@@ -56,7 +56,7 @@ class PresenceStatusRestServlet(RestServlet):
         state = yield self.presence_handler.get_state(target_user=user)
         state = format_user_presence_state(state, self.clock.time_msec())
 
-        defer.returnValue((200, state))
+        return (200, state)
 
     @defer.inlineCallbacks
     def on_PUT(self, request, user_id):
@@ -88,7 +88,7 @@ class PresenceStatusRestServlet(RestServlet):
         if self.hs.config.use_presence:
             yield self.presence_handler.set_state(user, state)
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
     def on_OPTIONS(self, request):
         return (200, {})
diff --git a/synapse/rest/client/v1/profile.py b/synapse/rest/client/v1/profile.py
index 4d8ab1f47e..2657ae45bb 100644
--- a/synapse/rest/client/v1/profile.py
+++ b/synapse/rest/client/v1/profile.py
@@ -48,7 +48,7 @@ class ProfileDisplaynameRestServlet(RestServlet):
         if displayname is not None:
             ret["displayname"] = displayname
 
-        defer.returnValue((200, ret))
+        return (200, ret)
 
     @defer.inlineCallbacks
     def on_PUT(self, request, user_id):
@@ -61,11 +61,11 @@ class ProfileDisplaynameRestServlet(RestServlet):
         try:
             new_name = content["displayname"]
         except Exception:
-            defer.returnValue((400, "Unable to parse name"))
+            return (400, "Unable to parse name")
 
         yield self.profile_handler.set_displayname(user, requester, new_name, is_admin)
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
     def on_OPTIONS(self, request, user_id):
         return (200, {})
@@ -98,7 +98,7 @@ class ProfileAvatarURLRestServlet(RestServlet):
         if avatar_url is not None:
             ret["avatar_url"] = avatar_url
 
-        defer.returnValue((200, ret))
+        return (200, ret)
 
     @defer.inlineCallbacks
     def on_PUT(self, request, user_id):
@@ -110,11 +110,11 @@ class ProfileAvatarURLRestServlet(RestServlet):
         try:
             new_name = content["avatar_url"]
         except Exception:
-            defer.returnValue((400, "Unable to parse name"))
+            return (400, "Unable to parse name")
 
         yield self.profile_handler.set_avatar_url(user, requester, new_name, is_admin)
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
     def on_OPTIONS(self, request, user_id):
         return (200, {})
@@ -150,7 +150,7 @@ class ProfileRestServlet(RestServlet):
         if avatar_url is not None:
             ret["avatar_url"] = avatar_url
 
-        defer.returnValue((200, ret))
+        return (200, ret)
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v1/push_rule.py b/synapse/rest/client/v1/push_rule.py
index e635efb420..c3ae8b98a8 100644
--- a/synapse/rest/client/v1/push_rule.py
+++ b/synapse/rest/client/v1/push_rule.py
@@ -69,7 +69,7 @@ class PushRuleRestServlet(RestServlet):
         if "attr" in spec:
             yield self.set_rule_attr(user_id, spec, content)
             self.notify_user(user_id)
-            defer.returnValue((200, {}))
+            return (200, {})
 
         if spec["rule_id"].startswith("."):
             # Rule ids starting with '.' are reserved for server default rules.
@@ -106,7 +106,7 @@ class PushRuleRestServlet(RestServlet):
         except RuleNotFoundException as e:
             raise SynapseError(400, str(e))
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, path):
@@ -123,7 +123,7 @@ class PushRuleRestServlet(RestServlet):
         try:
             yield self.store.delete_push_rule(user_id, namespaced_rule_id)
             self.notify_user(user_id)
-            defer.returnValue((200, {}))
+            return (200, {})
         except StoreError as e:
             if e.code == 404:
                 raise NotFoundError()
@@ -151,10 +151,10 @@ class PushRuleRestServlet(RestServlet):
             )
 
         if path[0] == "":
-            defer.returnValue((200, rules))
+            return (200, rules)
         elif path[0] == "global":
             result = _filter_ruleset_with_path(rules["global"], path[1:])
-            defer.returnValue((200, result))
+            return (200, result)
         else:
             raise UnrecognizedRequestError()
 
diff --git a/synapse/rest/client/v1/pusher.py b/synapse/rest/client/v1/pusher.py
index e9246018df..ebc3dec516 100644
--- a/synapse/rest/client/v1/pusher.py
+++ b/synapse/rest/client/v1/pusher.py
@@ -62,7 +62,7 @@ class PushersRestServlet(RestServlet):
                 if k not in allowed_keys:
                     del p[k]
 
-        defer.returnValue((200, {"pushers": pushers}))
+        return (200, {"pushers": pushers})
 
     def on_OPTIONS(self, _):
         return 200, {}
@@ -94,7 +94,7 @@ class PushersSetRestServlet(RestServlet):
             yield self.pusher_pool.remove_pusher(
                 content["app_id"], content["pushkey"], user_id=user.to_string()
             )
-            defer.returnValue((200, {}))
+            return (200, {})
 
         assert_params_in_dict(
             content,
@@ -143,7 +143,7 @@ class PushersSetRestServlet(RestServlet):
 
         self.notifier.on_new_replication_data()
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
     def on_OPTIONS(self, _):
         return 200, {}
@@ -190,7 +190,7 @@ class PushersRemoveRestServlet(RestServlet):
         )
         request.write(PushersRemoveRestServlet.SUCCESS_HTML)
         finish_request(request)
-        defer.returnValue(None)
+        return None
 
     def on_OPTIONS(self, _):
         return 200, {}
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index 7709c2d705..012e7a44a6 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -85,7 +85,7 @@ class RoomCreateRestServlet(TransactionRestServlet):
             requester, self.get_room_config(request)
         )
 
-        defer.returnValue((200, info))
+        return (200, info)
 
     def get_room_config(self, request):
         user_supplied_config = parse_json_object_from_request(request)
@@ -155,9 +155,9 @@ class RoomStateEventRestServlet(TransactionRestServlet):
 
         if format == "event":
             event = format_event_for_client_v2(data.get_dict())
-            defer.returnValue((200, event))
+            return (200, event)
         elif format == "content":
-            defer.returnValue((200, data.get_dict()["content"]))
+            return (200, data.get_dict()["content"])
 
     @defer.inlineCallbacks
     def on_PUT(self, request, room_id, event_type, state_key, txn_id=None):
@@ -192,7 +192,7 @@ class RoomStateEventRestServlet(TransactionRestServlet):
         ret = {}
         if event:
             ret = {"event_id": event.event_id}
-        defer.returnValue((200, ret))
+        return (200, ret)
 
 
 # TODO: Needs unit testing for generic events + feedback
@@ -226,7 +226,7 @@ class RoomSendEventRestServlet(TransactionRestServlet):
             requester, event_dict, txn_id=txn_id
         )
 
-        defer.returnValue((200, {"event_id": event.event_id}))
+        return (200, {"event_id": event.event_id})
 
     def on_GET(self, request, room_id, event_type, txn_id):
         return (200, "Not implemented")
@@ -289,7 +289,7 @@ class JoinRoomAliasServlet(TransactionRestServlet):
             third_party_signed=content.get("third_party_signed", None),
         )
 
-        defer.returnValue((200, {"room_id": room_id}))
+        return (200, {"room_id": room_id})
 
     def on_PUT(self, request, room_identifier, txn_id):
         return self.txns.fetch_or_execute_request(
@@ -342,7 +342,7 @@ class PublicRoomListRestServlet(TransactionRestServlet):
                 limit=limit, since_token=since_token
             )
 
-        defer.returnValue((200, data))
+        return (200, data)
 
     @defer.inlineCallbacks
     def on_POST(self, request):
@@ -387,7 +387,7 @@ class PublicRoomListRestServlet(TransactionRestServlet):
                 network_tuple=network_tuple,
             )
 
-        defer.returnValue((200, data))
+        return (200, data)
 
 
 # TODO: Needs unit testing
@@ -438,7 +438,7 @@ class RoomMemberListRestServlet(RestServlet):
                 continue
             chunk.append(event)
 
-        defer.returnValue((200, {"chunk": chunk}))
+        return (200, {"chunk": chunk})
 
 
 # deprecated in favour of /members?membership=join?
@@ -459,7 +459,7 @@ class JoinedRoomMemberListRestServlet(RestServlet):
             requester, room_id
         )
 
-        defer.returnValue((200, {"joined": users_with_profile}))
+        return (200, {"joined": users_with_profile})
 
 
 # TODO: Needs better unit testing
@@ -492,7 +492,7 @@ class RoomMessageListRestServlet(RestServlet):
             event_filter=event_filter,
         )
 
-        defer.returnValue((200, msgs))
+        return (200, msgs)
 
 
 # TODO: Needs unit testing
@@ -513,7 +513,7 @@ class RoomStateRestServlet(RestServlet):
             user_id=requester.user.to_string(),
             is_guest=requester.is_guest,
         )
-        defer.returnValue((200, events))
+        return (200, events)
 
 
 # TODO: Needs unit testing
@@ -532,7 +532,7 @@ class RoomInitialSyncRestServlet(RestServlet):
         content = yield self.initial_sync_handler.room_initial_sync(
             room_id=room_id, requester=requester, pagin_config=pagination_config
         )
-        defer.returnValue((200, content))
+        return (200, content)
 
 
 class RoomEventServlet(RestServlet):
@@ -555,9 +555,9 @@ class RoomEventServlet(RestServlet):
         time_now = self.clock.time_msec()
         if event:
             event = yield self._event_serializer.serialize_event(event, time_now)
-            defer.returnValue((200, event))
+            return (200, event)
         else:
-            defer.returnValue((404, "Event not found."))
+            return (404, "Event not found.")
 
 
 class RoomEventContextServlet(RestServlet):
@@ -607,7 +607,7 @@ class RoomEventContextServlet(RestServlet):
             results["state"], time_now
         )
 
-        defer.returnValue((200, results))
+        return (200, results)
 
 
 class RoomForgetRestServlet(TransactionRestServlet):
@@ -626,7 +626,7 @@ class RoomForgetRestServlet(TransactionRestServlet):
 
         yield self.room_member_handler.forget(user=requester.user, room_id=room_id)
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
     def on_PUT(self, request, room_id, txn_id):
         return self.txns.fetch_or_execute_request(
@@ -676,7 +676,7 @@ class RoomMembershipRestServlet(TransactionRestServlet):
                 requester,
                 txn_id,
             )
-            defer.returnValue((200, {}))
+            return (200, {})
             return
 
         target = requester.user
@@ -703,7 +703,7 @@ class RoomMembershipRestServlet(TransactionRestServlet):
         if membership_action == "join":
             return_value["room_id"] = room_id
 
-        defer.returnValue((200, return_value))
+        return (200, return_value)
 
     def _has_3pid_invite_keys(self, content):
         for key in {"id_server", "medium", "address"}:
@@ -745,7 +745,7 @@ class RoomRedactEventRestServlet(TransactionRestServlet):
             txn_id=txn_id,
         )
 
-        defer.returnValue((200, {"event_id": event.event_id}))
+        return (200, {"event_id": event.event_id})
 
     def on_PUT(self, request, room_id, event_id, txn_id):
         return self.txns.fetch_or_execute_request(
@@ -790,7 +790,7 @@ class RoomTypingRestServlet(RestServlet):
                 target_user=target_user, auth_user=requester.user, room_id=room_id
             )
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 class SearchRestServlet(RestServlet):
@@ -812,7 +812,7 @@ class SearchRestServlet(RestServlet):
             requester.user, content, batch
         )
 
-        defer.returnValue((200, results))
+        return (200, results)
 
 
 class JoinedRoomsRestServlet(RestServlet):
@@ -828,7 +828,7 @@ class JoinedRoomsRestServlet(RestServlet):
         requester = yield self.auth.get_user_by_req(request, allow_guest=True)
 
         room_ids = yield self.store.get_rooms_for_user(requester.user.to_string())
-        defer.returnValue((200, {"joined_rooms": list(room_ids)}))
+        return (200, {"joined_rooms": list(room_ids)})
 
 
 def register_txn_path(servlet, regex_string, http_server, with_get=False):
diff --git a/synapse/rest/client/v1/voip.py b/synapse/rest/client/v1/voip.py
index 41b3171ac8..497cddf8b8 100644
--- a/synapse/rest/client/v1/voip.py
+++ b/synapse/rest/client/v1/voip.py
@@ -60,18 +60,16 @@ class VoipRestServlet(RestServlet):
             password = turnPassword
 
         else:
-            defer.returnValue((200, {}))
-
-        defer.returnValue(
-            (
-                200,
-                {
-                    "username": username,
-                    "password": password,
-                    "ttl": userLifetime / 1000,
-                    "uris": turnUris,
-                },
-            )
+            return (200, {})
+
+        return (
+            200,
+            {
+                "username": username,
+                "password": password,
+                "ttl": userLifetime / 1000,
+                "uris": turnUris,
+            },
         )
 
     def on_OPTIONS(self, request):
diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index f143d8b85c..7ac456812a 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -117,7 +117,7 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
             # Wrap the session id in a JSON object
             ret = {"sid": sid}
 
-        defer.returnValue((200, ret))
+        return (200, ret)
 
     @defer.inlineCallbacks
     def send_password_reset(self, email, client_secret, send_attempt, next_link=None):
@@ -149,7 +149,7 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
             # Check that the send_attempt is higher than previous attempts
             if send_attempt <= last_send_attempt:
                 # If not, just return a success without sending an email
-                defer.returnValue(session_id)
+                return session_id
         else:
             # An non-validated session does not exist yet.
             # Generate a session id
@@ -185,7 +185,7 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
             token_expires,
         )
 
-        defer.returnValue(session_id)
+        return session_id
 
 
 class MsisdnPasswordRequestTokenRestServlet(RestServlet):
@@ -221,7 +221,7 @@ class MsisdnPasswordRequestTokenRestServlet(RestServlet):
             raise SynapseError(400, "MSISDN not found", Codes.THREEPID_NOT_FOUND)
 
         ret = yield self.identity_handler.requestMsisdnToken(**body)
-        defer.returnValue((200, ret))
+        return (200, ret)
 
 
 class PasswordResetSubmitTokenServlet(RestServlet):
@@ -279,7 +279,7 @@ class PasswordResetSubmitTokenServlet(RestServlet):
                     request.setResponseCode(302)
                     request.setHeader("Location", next_link)
                     finish_request(request)
-                    defer.returnValue(None)
+                    return None
 
             # Otherwise show the success template
             html = self.config.email_password_reset_success_html_content
@@ -295,7 +295,7 @@ class PasswordResetSubmitTokenServlet(RestServlet):
 
         request.write(html.encode("utf-8"))
         finish_request(request)
-        defer.returnValue(None)
+        return None
 
     def load_jinja2_template(self, template_dir, template_filename, template_vars):
         """Loads a jinja2 template with variables to insert
@@ -330,7 +330,7 @@ class PasswordResetSubmitTokenServlet(RestServlet):
         )
         response_code = 200 if valid else 400
 
-        defer.returnValue((response_code, {"success": valid}))
+        return (response_code, {"success": valid})
 
 
 class PasswordRestServlet(RestServlet):
@@ -399,7 +399,7 @@ class PasswordRestServlet(RestServlet):
 
         yield self._set_password_handler.set_password(user_id, new_password, requester)
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
     def on_OPTIONS(self, _):
         return 200, {}
@@ -434,7 +434,7 @@ class DeactivateAccountRestServlet(RestServlet):
             yield self._deactivate_account_handler.deactivate_account(
                 requester.user.to_string(), erase
             )
-            defer.returnValue((200, {}))
+            return (200, {})
 
         yield self.auth_handler.validate_user_via_ui_auth(
             requester, body, self.hs.get_ip_from_request(request)
@@ -447,7 +447,7 @@ class DeactivateAccountRestServlet(RestServlet):
         else:
             id_server_unbind_result = "no-support"
 
-        defer.returnValue((200, {"id_server_unbind_result": id_server_unbind_result}))
+        return (200, {"id_server_unbind_result": id_server_unbind_result})
 
 
 class EmailThreepidRequestTokenRestServlet(RestServlet):
@@ -481,7 +481,7 @@ class EmailThreepidRequestTokenRestServlet(RestServlet):
             raise SynapseError(400, "Email is already in use", Codes.THREEPID_IN_USE)
 
         ret = yield self.identity_handler.requestEmailToken(**body)
-        defer.returnValue((200, ret))
+        return (200, ret)
 
 
 class MsisdnThreepidRequestTokenRestServlet(RestServlet):
@@ -516,7 +516,7 @@ class MsisdnThreepidRequestTokenRestServlet(RestServlet):
             raise SynapseError(400, "MSISDN is already in use", Codes.THREEPID_IN_USE)
 
         ret = yield self.identity_handler.requestMsisdnToken(**body)
-        defer.returnValue((200, ret))
+        return (200, ret)
 
 
 class ThreepidRestServlet(RestServlet):
@@ -536,7 +536,7 @@ class ThreepidRestServlet(RestServlet):
 
         threepids = yield self.datastore.user_get_threepids(requester.user.to_string())
 
-        defer.returnValue((200, {"threepids": threepids}))
+        return (200, {"threepids": threepids})
 
     @defer.inlineCallbacks
     def on_POST(self, request):
@@ -568,7 +568,7 @@ class ThreepidRestServlet(RestServlet):
             logger.debug("Binding threepid %s to %s", threepid, user_id)
             yield self.identity_handler.bind_threepid(threePidCreds, user_id)
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 class ThreepidDeleteRestServlet(RestServlet):
@@ -603,7 +603,7 @@ class ThreepidDeleteRestServlet(RestServlet):
         else:
             id_server_unbind_result = "no-support"
 
-        defer.returnValue((200, {"id_server_unbind_result": id_server_unbind_result}))
+        return (200, {"id_server_unbind_result": id_server_unbind_result})
 
 
 class WhoamiRestServlet(RestServlet):
@@ -617,7 +617,7 @@ class WhoamiRestServlet(RestServlet):
     def on_GET(self, request):
         requester = yield self.auth.get_user_by_req(request)
 
-        defer.returnValue((200, {"user_id": requester.user.to_string()}))
+        return (200, {"user_id": requester.user.to_string()})
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/account_data.py b/synapse/rest/client/v2_alpha/account_data.py
index f155c26259..98f2f6f4b5 100644
--- a/synapse/rest/client/v2_alpha/account_data.py
+++ b/synapse/rest/client/v2_alpha/account_data.py
@@ -55,7 +55,7 @@ class AccountDataServlet(RestServlet):
 
         self.notifier.on_new_event("account_data_key", max_id, users=[user_id])
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
     @defer.inlineCallbacks
     def on_GET(self, request, user_id, account_data_type):
@@ -70,7 +70,7 @@ class AccountDataServlet(RestServlet):
         if event is None:
             raise NotFoundError("Account data not found")
 
-        defer.returnValue((200, event))
+        return (200, event)
 
 
 class RoomAccountDataServlet(RestServlet):
@@ -112,7 +112,7 @@ class RoomAccountDataServlet(RestServlet):
 
         self.notifier.on_new_event("account_data_key", max_id, users=[user_id])
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
     @defer.inlineCallbacks
     def on_GET(self, request, user_id, room_id, account_data_type):
@@ -127,7 +127,7 @@ class RoomAccountDataServlet(RestServlet):
         if event is None:
             raise NotFoundError("Room account data not found")
 
-        defer.returnValue((200, event))
+        return (200, event)
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/account_validity.py b/synapse/rest/client/v2_alpha/account_validity.py
index d29c10b83d..133c61900a 100644
--- a/synapse/rest/client/v2_alpha/account_validity.py
+++ b/synapse/rest/client/v2_alpha/account_validity.py
@@ -58,7 +58,7 @@ class AccountValidityRenewServlet(RestServlet):
         )
         request.write(AccountValidityRenewServlet.SUCCESS_HTML)
         finish_request(request)
-        defer.returnValue(None)
+        return None
 
 
 class AccountValiditySendMailServlet(RestServlet):
@@ -87,7 +87,7 @@ class AccountValiditySendMailServlet(RestServlet):
         user_id = requester.user.to_string()
         yield self.account_activity_handler.send_renewal_email_to_user(user_id)
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/auth.py b/synapse/rest/client/v2_alpha/auth.py
index bebc2951e7..f21aff39e5 100644
--- a/synapse/rest/client/v2_alpha/auth.py
+++ b/synapse/rest/client/v2_alpha/auth.py
@@ -207,7 +207,7 @@ class AuthRestServlet(RestServlet):
             request.write(html_bytes)
             finish_request(request)
 
-            defer.returnValue(None)
+            return None
         elif stagetype == LoginType.TERMS:
             if ("session" not in request.args or len(request.args["session"])) == 0:
                 raise SynapseError(400, "No session supplied")
@@ -239,7 +239,7 @@ class AuthRestServlet(RestServlet):
 
             request.write(html_bytes)
             finish_request(request)
-            defer.returnValue(None)
+            return None
         else:
             raise SynapseError(404, "Unknown auth stage type")
 
diff --git a/synapse/rest/client/v2_alpha/capabilities.py b/synapse/rest/client/v2_alpha/capabilities.py
index fc7e2f4dd5..a4fa45fe11 100644
--- a/synapse/rest/client/v2_alpha/capabilities.py
+++ b/synapse/rest/client/v2_alpha/capabilities.py
@@ -58,7 +58,7 @@ class CapabilitiesRestServlet(RestServlet):
                 "m.change_password": {"enabled": change_password},
             }
         }
-        defer.returnValue((200, response))
+        return (200, response)
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/devices.py b/synapse/rest/client/v2_alpha/devices.py
index d279229d74..9adf76cc0c 100644
--- a/synapse/rest/client/v2_alpha/devices.py
+++ b/synapse/rest/client/v2_alpha/devices.py
@@ -48,7 +48,7 @@ class DevicesRestServlet(RestServlet):
         devices = yield self.device_handler.get_devices_by_user(
             requester.user.to_string()
         )
-        defer.returnValue((200, {"devices": devices}))
+        return (200, {"devices": devices})
 
 
 class DeleteDevicesRestServlet(RestServlet):
@@ -91,7 +91,7 @@ class DeleteDevicesRestServlet(RestServlet):
         yield self.device_handler.delete_devices(
             requester.user.to_string(), body["devices"]
         )
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 class DeviceRestServlet(RestServlet):
@@ -114,7 +114,7 @@ class DeviceRestServlet(RestServlet):
         device = yield self.device_handler.get_device(
             requester.user.to_string(), device_id
         )
-        defer.returnValue((200, device))
+        return (200, device)
 
     @interactive_auth_handler
     @defer.inlineCallbacks
@@ -137,7 +137,7 @@ class DeviceRestServlet(RestServlet):
         )
 
         yield self.device_handler.delete_device(requester.user.to_string(), device_id)
-        defer.returnValue((200, {}))
+        return (200, {})
 
     @defer.inlineCallbacks
     def on_PUT(self, request, device_id):
@@ -147,7 +147,7 @@ class DeviceRestServlet(RestServlet):
         yield self.device_handler.update_device(
             requester.user.to_string(), device_id, body
         )
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/filter.py b/synapse/rest/client/v2_alpha/filter.py
index 3f0adf4a21..22be0ee3c5 100644
--- a/synapse/rest/client/v2_alpha/filter.py
+++ b/synapse/rest/client/v2_alpha/filter.py
@@ -56,7 +56,7 @@ class GetFilterRestServlet(RestServlet):
                 user_localpart=target_user.localpart, filter_id=filter_id
             )
 
-            defer.returnValue((200, filter.get_filter_json()))
+            return (200, filter.get_filter_json())
         except (KeyError, StoreError):
             raise SynapseError(400, "No such filter", errcode=Codes.NOT_FOUND)
 
@@ -89,7 +89,7 @@ class CreateFilterRestServlet(RestServlet):
             user_localpart=target_user.localpart, user_filter=content
         )
 
-        defer.returnValue((200, {"filter_id": str(filter_id)}))
+        return (200, {"filter_id": str(filter_id)})
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/groups.py b/synapse/rest/client/v2_alpha/groups.py
index a312dd2593..e629c4256d 100644
--- a/synapse/rest/client/v2_alpha/groups.py
+++ b/synapse/rest/client/v2_alpha/groups.py
@@ -47,7 +47,7 @@ class GroupServlet(RestServlet):
             group_id, requester_user_id
         )
 
-        defer.returnValue((200, group_description))
+        return (200, group_description)
 
     @defer.inlineCallbacks
     def on_POST(self, request, group_id):
@@ -59,7 +59,7 @@ class GroupServlet(RestServlet):
             group_id, requester_user_id, content
         )
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 class GroupSummaryServlet(RestServlet):
@@ -83,7 +83,7 @@ class GroupSummaryServlet(RestServlet):
             group_id, requester_user_id
         )
 
-        defer.returnValue((200, get_group_summary))
+        return (200, get_group_summary)
 
 
 class GroupSummaryRoomsCatServlet(RestServlet):
@@ -120,7 +120,7 @@ class GroupSummaryRoomsCatServlet(RestServlet):
             content=content,
         )
 
-        defer.returnValue((200, resp))
+        return (200, resp)
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, group_id, category_id, room_id):
@@ -131,7 +131,7 @@ class GroupSummaryRoomsCatServlet(RestServlet):
             group_id, requester_user_id, room_id=room_id, category_id=category_id
         )
 
-        defer.returnValue((200, resp))
+        return (200, resp)
 
 
 class GroupCategoryServlet(RestServlet):
@@ -157,7 +157,7 @@ class GroupCategoryServlet(RestServlet):
             group_id, requester_user_id, category_id=category_id
         )
 
-        defer.returnValue((200, category))
+        return (200, category)
 
     @defer.inlineCallbacks
     def on_PUT(self, request, group_id, category_id):
@@ -169,7 +169,7 @@ class GroupCategoryServlet(RestServlet):
             group_id, requester_user_id, category_id=category_id, content=content
         )
 
-        defer.returnValue((200, resp))
+        return (200, resp)
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, group_id, category_id):
@@ -180,7 +180,7 @@ class GroupCategoryServlet(RestServlet):
             group_id, requester_user_id, category_id=category_id
         )
 
-        defer.returnValue((200, resp))
+        return (200, resp)
 
 
 class GroupCategoriesServlet(RestServlet):
@@ -204,7 +204,7 @@ class GroupCategoriesServlet(RestServlet):
             group_id, requester_user_id
         )
 
-        defer.returnValue((200, category))
+        return (200, category)
 
 
 class GroupRoleServlet(RestServlet):
@@ -228,7 +228,7 @@ class GroupRoleServlet(RestServlet):
             group_id, requester_user_id, role_id=role_id
         )
 
-        defer.returnValue((200, category))
+        return (200, category)
 
     @defer.inlineCallbacks
     def on_PUT(self, request, group_id, role_id):
@@ -240,7 +240,7 @@ class GroupRoleServlet(RestServlet):
             group_id, requester_user_id, role_id=role_id, content=content
         )
 
-        defer.returnValue((200, resp))
+        return (200, resp)
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, group_id, role_id):
@@ -251,7 +251,7 @@ class GroupRoleServlet(RestServlet):
             group_id, requester_user_id, role_id=role_id
         )
 
-        defer.returnValue((200, resp))
+        return (200, resp)
 
 
 class GroupRolesServlet(RestServlet):
@@ -275,7 +275,7 @@ class GroupRolesServlet(RestServlet):
             group_id, requester_user_id
         )
 
-        defer.returnValue((200, category))
+        return (200, category)
 
 
 class GroupSummaryUsersRoleServlet(RestServlet):
@@ -312,7 +312,7 @@ class GroupSummaryUsersRoleServlet(RestServlet):
             content=content,
         )
 
-        defer.returnValue((200, resp))
+        return (200, resp)
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, group_id, role_id, user_id):
@@ -323,7 +323,7 @@ class GroupSummaryUsersRoleServlet(RestServlet):
             group_id, requester_user_id, user_id=user_id, role_id=role_id
         )
 
-        defer.returnValue((200, resp))
+        return (200, resp)
 
 
 class GroupRoomServlet(RestServlet):
@@ -347,7 +347,7 @@ class GroupRoomServlet(RestServlet):
             group_id, requester_user_id
         )
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class GroupUsersServlet(RestServlet):
@@ -371,7 +371,7 @@ class GroupUsersServlet(RestServlet):
             group_id, requester_user_id
         )
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class GroupInvitedUsersServlet(RestServlet):
@@ -395,7 +395,7 @@ class GroupInvitedUsersServlet(RestServlet):
             group_id, requester_user_id
         )
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class GroupSettingJoinPolicyServlet(RestServlet):
@@ -420,7 +420,7 @@ class GroupSettingJoinPolicyServlet(RestServlet):
             group_id, requester_user_id, content
         )
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class GroupCreateServlet(RestServlet):
@@ -450,7 +450,7 @@ class GroupCreateServlet(RestServlet):
             group_id, requester_user_id, content
         )
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class GroupAdminRoomsServlet(RestServlet):
@@ -477,7 +477,7 @@ class GroupAdminRoomsServlet(RestServlet):
             group_id, requester_user_id, room_id, content
         )
 
-        defer.returnValue((200, result))
+        return (200, result)
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, group_id, room_id):
@@ -488,7 +488,7 @@ class GroupAdminRoomsServlet(RestServlet):
             group_id, requester_user_id, room_id
         )
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class GroupAdminRoomsConfigServlet(RestServlet):
@@ -516,7 +516,7 @@ class GroupAdminRoomsConfigServlet(RestServlet):
             group_id, requester_user_id, room_id, config_key, content
         )
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class GroupAdminUsersInviteServlet(RestServlet):
@@ -546,7 +546,7 @@ class GroupAdminUsersInviteServlet(RestServlet):
             group_id, user_id, requester_user_id, config
         )
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class GroupAdminUsersKickServlet(RestServlet):
@@ -573,7 +573,7 @@ class GroupAdminUsersKickServlet(RestServlet):
             group_id, user_id, requester_user_id, content
         )
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class GroupSelfLeaveServlet(RestServlet):
@@ -598,7 +598,7 @@ class GroupSelfLeaveServlet(RestServlet):
             group_id, requester_user_id, requester_user_id, content
         )
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class GroupSelfJoinServlet(RestServlet):
@@ -623,7 +623,7 @@ class GroupSelfJoinServlet(RestServlet):
             group_id, requester_user_id, content
         )
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class GroupSelfAcceptInviteServlet(RestServlet):
@@ -648,7 +648,7 @@ class GroupSelfAcceptInviteServlet(RestServlet):
             group_id, requester_user_id, content
         )
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class GroupSelfUpdatePublicityServlet(RestServlet):
@@ -672,7 +672,7 @@ class GroupSelfUpdatePublicityServlet(RestServlet):
         publicise = content["publicise"]
         yield self.store.update_group_publicity(group_id, requester_user_id, publicise)
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 class PublicisedGroupsForUserServlet(RestServlet):
@@ -694,7 +694,7 @@ class PublicisedGroupsForUserServlet(RestServlet):
 
         result = yield self.groups_handler.get_publicised_groups_for_user(user_id)
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class PublicisedGroupsForUsersServlet(RestServlet):
@@ -719,7 +719,7 @@ class PublicisedGroupsForUsersServlet(RestServlet):
 
         result = yield self.groups_handler.bulk_get_publicised_groups(user_ids)
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class GroupsForUserServlet(RestServlet):
@@ -741,7 +741,7 @@ class GroupsForUserServlet(RestServlet):
 
         result = yield self.groups_handler.get_joined_groups(requester_user_id)
 
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/keys.py b/synapse/rest/client/v2_alpha/keys.py
index 45c9928b65..6008adec7c 100644
--- a/synapse/rest/client/v2_alpha/keys.py
+++ b/synapse/rest/client/v2_alpha/keys.py
@@ -95,7 +95,7 @@ class KeyUploadServlet(RestServlet):
         result = yield self.e2e_keys_handler.upload_keys_for_user(
             user_id, device_id, body
         )
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class KeyQueryServlet(RestServlet):
@@ -149,7 +149,7 @@ class KeyQueryServlet(RestServlet):
         timeout = parse_integer(request, "timeout", 10 * 1000)
         body = parse_json_object_from_request(request)
         result = yield self.e2e_keys_handler.query_devices(body, timeout)
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 class KeyChangesServlet(RestServlet):
@@ -189,7 +189,7 @@ class KeyChangesServlet(RestServlet):
 
         results = yield self.device_handler.get_user_ids_changed(user_id, from_token)
 
-        defer.returnValue((200, results))
+        return (200, results)
 
 
 class OneTimeKeyServlet(RestServlet):
@@ -224,7 +224,7 @@ class OneTimeKeyServlet(RestServlet):
         timeout = parse_integer(request, "timeout", 10 * 1000)
         body = parse_json_object_from_request(request)
         result = yield self.e2e_keys_handler.claim_one_time_keys(body, timeout)
-        defer.returnValue((200, result))
+        return (200, result)
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/notifications.py b/synapse/rest/client/v2_alpha/notifications.py
index 728a52328f..d034863a3c 100644
--- a/synapse/rest/client/v2_alpha/notifications.py
+++ b/synapse/rest/client/v2_alpha/notifications.py
@@ -88,9 +88,7 @@ class NotificationsServlet(RestServlet):
             returned_push_actions.append(returned_pa)
             next_token = str(pa["stream_ordering"])
 
-        defer.returnValue(
-            (200, {"notifications": returned_push_actions, "next_token": next_token})
-        )
+        return (200, {"notifications": returned_push_actions, "next_token": next_token})
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/openid.py b/synapse/rest/client/v2_alpha/openid.py
index b1b5385b09..b4925c0f59 100644
--- a/synapse/rest/client/v2_alpha/openid.py
+++ b/synapse/rest/client/v2_alpha/openid.py
@@ -83,16 +83,14 @@ class IdTokenServlet(RestServlet):
 
         yield self.store.insert_open_id_token(token, ts_valid_until_ms, user_id)
 
-        defer.returnValue(
-            (
-                200,
-                {
-                    "access_token": token,
-                    "token_type": "Bearer",
-                    "matrix_server_name": self.server_name,
-                    "expires_in": self.EXPIRES_MS / 1000,
-                },
-            )
+        return (
+            200,
+            {
+                "access_token": token,
+                "token_type": "Bearer",
+                "matrix_server_name": self.server_name,
+                "expires_in": self.EXPIRES_MS / 1000,
+            },
         )
 
 
diff --git a/synapse/rest/client/v2_alpha/read_marker.py b/synapse/rest/client/v2_alpha/read_marker.py
index e75664279b..d93d6a9f24 100644
--- a/synapse/rest/client/v2_alpha/read_marker.py
+++ b/synapse/rest/client/v2_alpha/read_marker.py
@@ -59,7 +59,7 @@ class ReadMarkerRestServlet(RestServlet):
                 event_id=read_marker_event_id,
             )
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/receipts.py b/synapse/rest/client/v2_alpha/receipts.py
index 488905626a..98a97b7059 100644
--- a/synapse/rest/client/v2_alpha/receipts.py
+++ b/synapse/rest/client/v2_alpha/receipts.py
@@ -52,7 +52,7 @@ class ReceiptRestServlet(RestServlet):
             room_id, receipt_type, user_id=requester.user.to_string(), event_id=event_id
         )
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/register.py b/synapse/rest/client/v2_alpha/register.py
index f327999e59..05ea1459e3 100644
--- a/synapse/rest/client/v2_alpha/register.py
+++ b/synapse/rest/client/v2_alpha/register.py
@@ -95,7 +95,7 @@ class EmailRegisterRequestTokenRestServlet(RestServlet):
             raise SynapseError(400, "Email is already in use", Codes.THREEPID_IN_USE)
 
         ret = yield self.identity_handler.requestEmailToken(**body)
-        defer.returnValue((200, ret))
+        return (200, ret)
 
 
 class MsisdnRegisterRequestTokenRestServlet(RestServlet):
@@ -138,7 +138,7 @@ class MsisdnRegisterRequestTokenRestServlet(RestServlet):
             )
 
         ret = yield self.identity_handler.requestMsisdnToken(**body)
-        defer.returnValue((200, ret))
+        return (200, ret)
 
 
 class UsernameAvailabilityRestServlet(RestServlet):
@@ -178,7 +178,7 @@ class UsernameAvailabilityRestServlet(RestServlet):
 
             yield self.registration_handler.check_username(username)
 
-            defer.returnValue((200, {"available": True}))
+            return (200, {"available": True})
 
 
 class RegisterRestServlet(RestServlet):
@@ -230,7 +230,7 @@ class RegisterRestServlet(RestServlet):
 
         if kind == b"guest":
             ret = yield self._do_guest_registration(body, address=client_addr)
-            defer.returnValue(ret)
+            return ret
             return
         elif kind != b"user":
             raise UnrecognizedRequestError(
@@ -282,7 +282,7 @@ class RegisterRestServlet(RestServlet):
                 result = yield self._do_appservice_registration(
                     desired_username, access_token, body
                 )
-            defer.returnValue((200, result))  # we throw for non 200 responses
+            return (200, result)  # we throw for non 200 responses
             return
 
         # for either shared secret or regular registration, downcase the
@@ -301,7 +301,7 @@ class RegisterRestServlet(RestServlet):
             result = yield self._do_shared_secret_registration(
                 desired_username, desired_password, body
             )
-            defer.returnValue((200, result))  # we throw for non 200 responses
+            return (200, result)  # we throw for non 200 responses
             return
 
         # == Normal User Registration == (everyone else)
@@ -500,7 +500,7 @@ class RegisterRestServlet(RestServlet):
                 bind_msisdn=params.get("bind_msisdn"),
             )
 
-        defer.returnValue((200, return_dict))
+        return (200, return_dict)
 
     def on_OPTIONS(self, _):
         return 200, {}
@@ -510,7 +510,7 @@ class RegisterRestServlet(RestServlet):
         user_id = yield self.registration_handler.appservice_register(
             username, as_token
         )
-        defer.returnValue((yield self._create_registration_details(user_id, body)))
+        return (yield self._create_registration_details(user_id, body))
 
     @defer.inlineCallbacks
     def _do_shared_secret_registration(self, username, password, body):
@@ -546,7 +546,7 @@ class RegisterRestServlet(RestServlet):
         )
 
         result = yield self._create_registration_details(user_id, body)
-        defer.returnValue(result)
+        return result
 
     @defer.inlineCallbacks
     def _create_registration_details(self, user_id, params):
@@ -570,7 +570,7 @@ class RegisterRestServlet(RestServlet):
             )
 
             result.update({"access_token": access_token, "device_id": device_id})
-        defer.returnValue(result)
+        return result
 
     @defer.inlineCallbacks
     def _do_guest_registration(self, params, address=None):
@@ -588,16 +588,14 @@ class RegisterRestServlet(RestServlet):
             user_id, device_id, initial_display_name, is_guest=True
         )
 
-        defer.returnValue(
-            (
-                200,
-                {
-                    "user_id": user_id,
-                    "device_id": device_id,
-                    "access_token": access_token,
-                    "home_server": self.hs.hostname,
-                },
-            )
+        return (
+            200,
+            {
+                "user_id": user_id,
+                "device_id": device_id,
+                "access_token": access_token,
+                "home_server": self.hs.hostname,
+            },
         )
 
 
diff --git a/synapse/rest/client/v2_alpha/relations.py b/synapse/rest/client/v2_alpha/relations.py
index 6e52f6d284..6fde3decdb 100644
--- a/synapse/rest/client/v2_alpha/relations.py
+++ b/synapse/rest/client/v2_alpha/relations.py
@@ -116,7 +116,7 @@ class RelationSendServlet(RestServlet):
             requester, event_dict=event_dict, txn_id=txn_id
         )
 
-        defer.returnValue((200, {"event_id": event.event_id}))
+        return (200, {"event_id": event.event_id})
 
 
 class RelationPaginationServlet(RestServlet):
@@ -196,7 +196,7 @@ class RelationPaginationServlet(RestServlet):
         return_value["chunk"] = events
         return_value["original_event"] = original_event
 
-        defer.returnValue((200, return_value))
+        return (200, return_value)
 
 
 class RelationAggregationPaginationServlet(RestServlet):
@@ -268,7 +268,7 @@ class RelationAggregationPaginationServlet(RestServlet):
                 to_token=to_token,
             )
 
-        defer.returnValue((200, pagination_chunk.to_dict()))
+        return (200, pagination_chunk.to_dict())
 
 
 class RelationAggregationGroupPaginationServlet(RestServlet):
@@ -354,7 +354,7 @@ class RelationAggregationGroupPaginationServlet(RestServlet):
         return_value = result.to_dict()
         return_value["chunk"] = events
 
-        defer.returnValue((200, return_value))
+        return (200, return_value)
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/report_event.py b/synapse/rest/client/v2_alpha/report_event.py
index e7578af804..3fdd4584a3 100644
--- a/synapse/rest/client/v2_alpha/report_event.py
+++ b/synapse/rest/client/v2_alpha/report_event.py
@@ -72,7 +72,7 @@ class ReportEventRestServlet(RestServlet):
             received_ts=self.clock.time_msec(),
         )
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/room_keys.py b/synapse/rest/client/v2_alpha/room_keys.py
index 8d1b810565..10dec96208 100644
--- a/synapse/rest/client/v2_alpha/room_keys.py
+++ b/synapse/rest/client/v2_alpha/room_keys.py
@@ -135,7 +135,7 @@ class RoomKeysServlet(RestServlet):
             body = {"rooms": {room_id: body}}
 
         yield self.e2e_room_keys_handler.upload_room_keys(user_id, version, body)
-        defer.returnValue((200, {}))
+        return (200, {})
 
     @defer.inlineCallbacks
     def on_GET(self, request, room_id, session_id):
@@ -218,7 +218,7 @@ class RoomKeysServlet(RestServlet):
             else:
                 room_keys = room_keys["rooms"][room_id]
 
-        defer.returnValue((200, room_keys))
+        return (200, room_keys)
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, room_id, session_id):
@@ -242,7 +242,7 @@ class RoomKeysServlet(RestServlet):
         yield self.e2e_room_keys_handler.delete_room_keys(
             user_id, version, room_id, session_id
         )
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 class RoomKeysNewVersionServlet(RestServlet):
@@ -293,7 +293,7 @@ class RoomKeysNewVersionServlet(RestServlet):
         info = parse_json_object_from_request(request)
 
         new_version = yield self.e2e_room_keys_handler.create_version(user_id, info)
-        defer.returnValue((200, {"version": new_version}))
+        return (200, {"version": new_version})
 
     # we deliberately don't have a PUT /version, as these things really should
     # be immutable to avoid people footgunning
@@ -338,7 +338,7 @@ class RoomKeysVersionServlet(RestServlet):
         except SynapseError as e:
             if e.code == 404:
                 raise SynapseError(404, "No backup found", Codes.NOT_FOUND)
-        defer.returnValue((200, info))
+        return (200, info)
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, version):
@@ -358,7 +358,7 @@ class RoomKeysVersionServlet(RestServlet):
         user_id = requester.user.to_string()
 
         yield self.e2e_room_keys_handler.delete_version(user_id, version)
-        defer.returnValue((200, {}))
+        return (200, {})
 
     @defer.inlineCallbacks
     def on_PUT(self, request, version):
@@ -392,7 +392,7 @@ class RoomKeysVersionServlet(RestServlet):
             )
 
         yield self.e2e_room_keys_handler.update_version(user_id, version, info)
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/room_upgrade_rest_servlet.py b/synapse/rest/client/v2_alpha/room_upgrade_rest_servlet.py
index d7f7faa029..14ba61a63e 100644
--- a/synapse/rest/client/v2_alpha/room_upgrade_rest_servlet.py
+++ b/synapse/rest/client/v2_alpha/room_upgrade_rest_servlet.py
@@ -80,7 +80,7 @@ class RoomUpgradeRestServlet(RestServlet):
 
         ret = {"replacement_room": new_room_id}
 
-        defer.returnValue((200, ret))
+        return (200, ret)
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/sendtodevice.py b/synapse/rest/client/v2_alpha/sendtodevice.py
index 78075b8fc0..2613648d82 100644
--- a/synapse/rest/client/v2_alpha/sendtodevice.py
+++ b/synapse/rest/client/v2_alpha/sendtodevice.py
@@ -60,7 +60,7 @@ class SendToDeviceRestServlet(servlet.RestServlet):
         )
 
         response = (200, {})
-        defer.returnValue(response)
+        return response
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/sync.py b/synapse/rest/client/v2_alpha/sync.py
index 02d56dee6c..7b32dd2212 100644
--- a/synapse/rest/client/v2_alpha/sync.py
+++ b/synapse/rest/client/v2_alpha/sync.py
@@ -174,7 +174,7 @@ class SyncRestServlet(RestServlet):
             time_now, sync_result, requester.access_token_id, filter
         )
 
-        defer.returnValue((200, response_content))
+        return (200, response_content)
 
     @defer.inlineCallbacks
     def encode_response(self, time_now, sync_result, access_token_id, filter):
@@ -205,27 +205,23 @@ class SyncRestServlet(RestServlet):
             event_formatter,
         )
 
-        defer.returnValue(
-            {
-                "account_data": {"events": sync_result.account_data},
-                "to_device": {"events": sync_result.to_device},
-                "device_lists": {
-                    "changed": list(sync_result.device_lists.changed),
-                    "left": list(sync_result.device_lists.left),
-                },
-                "presence": SyncRestServlet.encode_presence(
-                    sync_result.presence, time_now
-                ),
-                "rooms": {"join": joined, "invite": invited, "leave": archived},
-                "groups": {
-                    "join": sync_result.groups.join,
-                    "invite": sync_result.groups.invite,
-                    "leave": sync_result.groups.leave,
-                },
-                "device_one_time_keys_count": sync_result.device_one_time_keys_count,
-                "next_batch": sync_result.next_batch.to_string(),
-            }
-        )
+        return {
+            "account_data": {"events": sync_result.account_data},
+            "to_device": {"events": sync_result.to_device},
+            "device_lists": {
+                "changed": list(sync_result.device_lists.changed),
+                "left": list(sync_result.device_lists.left),
+            },
+            "presence": SyncRestServlet.encode_presence(sync_result.presence, time_now),
+            "rooms": {"join": joined, "invite": invited, "leave": archived},
+            "groups": {
+                "join": sync_result.groups.join,
+                "invite": sync_result.groups.invite,
+                "leave": sync_result.groups.leave,
+            },
+            "device_one_time_keys_count": sync_result.device_one_time_keys_count,
+            "next_batch": sync_result.next_batch.to_string(),
+        }
 
     @staticmethod
     def encode_presence(events, time_now):
@@ -273,7 +269,7 @@ class SyncRestServlet(RestServlet):
                 event_formatter=event_formatter,
             )
 
-        defer.returnValue(joined)
+        return joined
 
     @defer.inlineCallbacks
     def encode_invited(self, rooms, time_now, token_id, event_formatter):
@@ -309,7 +305,7 @@ class SyncRestServlet(RestServlet):
             invited_state.append(invite)
             invited[room.room_id] = {"invite_state": {"events": invited_state}}
 
-        defer.returnValue(invited)
+        return invited
 
     @defer.inlineCallbacks
     def encode_archived(self, rooms, time_now, token_id, event_fields, event_formatter):
@@ -342,7 +338,7 @@ class SyncRestServlet(RestServlet):
                 event_formatter=event_formatter,
             )
 
-        defer.returnValue(joined)
+        return joined
 
     @defer.inlineCallbacks
     def encode_room(
@@ -414,7 +410,7 @@ class SyncRestServlet(RestServlet):
             result["unread_notifications"] = room.unread_notifications
             result["summary"] = room.summary
 
-        defer.returnValue(result)
+        return result
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/tags.py b/synapse/rest/client/v2_alpha/tags.py
index 07b6ede603..d173544355 100644
--- a/synapse/rest/client/v2_alpha/tags.py
+++ b/synapse/rest/client/v2_alpha/tags.py
@@ -45,7 +45,7 @@ class TagListServlet(RestServlet):
 
         tags = yield self.store.get_tags_for_room(user_id, room_id)
 
-        defer.returnValue((200, {"tags": tags}))
+        return (200, {"tags": tags})
 
 
 class TagServlet(RestServlet):
@@ -76,7 +76,7 @@ class TagServlet(RestServlet):
 
         self.notifier.on_new_event("account_data_key", max_id, users=[user_id])
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, user_id, room_id, tag):
@@ -88,7 +88,7 @@ class TagServlet(RestServlet):
 
         self.notifier.on_new_event("account_data_key", max_id, users=[user_id])
 
-        defer.returnValue((200, {}))
+        return (200, {})
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/thirdparty.py b/synapse/rest/client/v2_alpha/thirdparty.py
index 1e66662a05..158e686b01 100644
--- a/synapse/rest/client/v2_alpha/thirdparty.py
+++ b/synapse/rest/client/v2_alpha/thirdparty.py
@@ -40,7 +40,7 @@ class ThirdPartyProtocolsServlet(RestServlet):
         yield self.auth.get_user_by_req(request, allow_guest=True)
 
         protocols = yield self.appservice_handler.get_3pe_protocols()
-        defer.returnValue((200, protocols))
+        return (200, protocols)
 
 
 class ThirdPartyProtocolServlet(RestServlet):
@@ -60,9 +60,9 @@ class ThirdPartyProtocolServlet(RestServlet):
             only_protocol=protocol
         )
         if protocol in protocols:
-            defer.returnValue((200, protocols[protocol]))
+            return (200, protocols[protocol])
         else:
-            defer.returnValue((404, {"error": "Unknown protocol"}))
+            return (404, {"error": "Unknown protocol"})
 
 
 class ThirdPartyUserServlet(RestServlet):
@@ -85,7 +85,7 @@ class ThirdPartyUserServlet(RestServlet):
             ThirdPartyEntityKind.USER, protocol, fields
         )
 
-        defer.returnValue((200, results))
+        return (200, results)
 
 
 class ThirdPartyLocationServlet(RestServlet):
@@ -108,7 +108,7 @@ class ThirdPartyLocationServlet(RestServlet):
             ThirdPartyEntityKind.LOCATION, protocol, fields
         )
 
-        defer.returnValue((200, results))
+        return (200, results)
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/user_directory.py b/synapse/rest/client/v2_alpha/user_directory.py
index e19fb6d583..7ab2b80e46 100644
--- a/synapse/rest/client/v2_alpha/user_directory.py
+++ b/synapse/rest/client/v2_alpha/user_directory.py
@@ -60,7 +60,7 @@ class UserDirectorySearchRestServlet(RestServlet):
         user_id = requester.user.to_string()
 
         if not self.hs.config.user_directory_search_enabled:
-            defer.returnValue((200, {"limited": False, "results": []}))
+            return (200, {"limited": False, "results": []})
 
         body = parse_json_object_from_request(request)
 
@@ -76,7 +76,7 @@ class UserDirectorySearchRestServlet(RestServlet):
             user_id, search_term, limit
         )
 
-        defer.returnValue((200, results))
+        return (200, results)
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 65afffbb42..92beefa176 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -171,7 +171,7 @@ class MediaRepository(object):
 
         yield self._generate_thumbnails(None, media_id, media_id, media_type)
 
-        defer.returnValue("mxc://%s/%s" % (self.server_name, media_id))
+        return "mxc://%s/%s" % (self.server_name, media_id)
 
     @defer.inlineCallbacks
     def get_local_media(self, request, media_id, name):
@@ -282,7 +282,7 @@ class MediaRepository(object):
             with responder:
                 pass
 
-        defer.returnValue(media_info)
+        return media_info
 
     @defer.inlineCallbacks
     def _get_remote_media_impl(self, server_name, media_id):
@@ -317,14 +317,14 @@ class MediaRepository(object):
 
             responder = yield self.media_storage.fetch_media(file_info)
             if responder:
-                defer.returnValue((responder, media_info))
+                return (responder, media_info)
 
         # Failed to find the file anywhere, lets download it.
 
         media_info = yield self._download_remote_file(server_name, media_id, file_id)
 
         responder = yield self.media_storage.fetch_media(file_info)
-        defer.returnValue((responder, media_info))
+        return (responder, media_info)
 
     @defer.inlineCallbacks
     def _download_remote_file(self, server_name, media_id, file_id):
@@ -421,7 +421,7 @@ class MediaRepository(object):
 
         yield self._generate_thumbnails(server_name, media_id, file_id, media_type)
 
-        defer.returnValue(media_info)
+        return media_info
 
     def _get_thumbnail_requirements(self, media_type):
         return self.thumbnail_requirements.get(media_type, ())
@@ -500,7 +500,7 @@ class MediaRepository(object):
                 media_id, t_width, t_height, t_type, t_method, t_len
             )
 
-            defer.returnValue(output_path)
+            return output_path
 
     @defer.inlineCallbacks
     def generate_remote_exact_thumbnail(
@@ -554,7 +554,7 @@ class MediaRepository(object):
                 t_len,
             )
 
-            defer.returnValue(output_path)
+            return output_path
 
     @defer.inlineCallbacks
     def _generate_thumbnails(
@@ -667,7 +667,7 @@ class MediaRepository(object):
                     media_id, t_width, t_height, t_type, t_method, t_len
                 )
 
-        defer.returnValue({"width": m_width, "height": m_height})
+        return {"width": m_width, "height": m_height}
 
     @defer.inlineCallbacks
     def delete_old_remote_media(self, before_ts):
@@ -704,7 +704,7 @@ class MediaRepository(object):
                 yield self.store.delete_remote_media(origin, media_id)
                 deleted += 1
 
-        defer.returnValue({"deleted": deleted})
+        return {"deleted": deleted}
 
 
 class MediaRepositoryResource(Resource):
diff --git a/synapse/rest/media/v1/media_storage.py b/synapse/rest/media/v1/media_storage.py
index 25e5ac2848..3b87717a5a 100644
--- a/synapse/rest/media/v1/media_storage.py
+++ b/synapse/rest/media/v1/media_storage.py
@@ -69,7 +69,7 @@ class MediaStorage(object):
             )
             yield finish_cb()
 
-        defer.returnValue(fname)
+        return fname
 
     @contextlib.contextmanager
     def store_into_file(self, file_info):
@@ -143,14 +143,14 @@ class MediaStorage(object):
         path = self._file_info_to_path(file_info)
         local_path = os.path.join(self.local_media_directory, path)
         if os.path.exists(local_path):
-            defer.returnValue(FileResponder(open(local_path, "rb")))
+            return FileResponder(open(local_path, "rb"))
 
         for provider in self.storage_providers:
             res = yield provider.fetch(path, file_info)
             if res:
-                defer.returnValue(res)
+                return res
 
-        defer.returnValue(None)
+        return None
 
     @defer.inlineCallbacks
     def ensure_media_is_in_local_cache(self, file_info):
@@ -166,7 +166,7 @@ class MediaStorage(object):
         path = self._file_info_to_path(file_info)
         local_path = os.path.join(self.local_media_directory, path)
         if os.path.exists(local_path):
-            defer.returnValue(local_path)
+            return local_path
 
         dirname = os.path.dirname(local_path)
         if not os.path.exists(dirname):
@@ -181,7 +181,7 @@ class MediaStorage(object):
                     )
                     yield res.write_to_consumer(consumer)
                     yield consumer.wait()
-                defer.returnValue(local_path)
+                return local_path
 
         raise Exception("file could not be found")
 
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index 5871737bfd..bd40891a7f 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -182,7 +182,7 @@ class PreviewUrlResource(DirectServeResource):
             og = cache_result["og"]
             if isinstance(og, six.text_type):
                 og = og.encode("utf8")
-            defer.returnValue(og)
+            return og
             return
 
         media_info = yield self._download_url(url, user)
@@ -284,7 +284,7 @@ class PreviewUrlResource(DirectServeResource):
             media_info["created_ts"],
         )
 
-        defer.returnValue(jsonog)
+        return jsonog
 
     @defer.inlineCallbacks
     def _download_url(self, url, user):
@@ -354,22 +354,20 @@ class PreviewUrlResource(DirectServeResource):
             # therefore not expire it.
             raise
 
-        defer.returnValue(
-            {
-                "media_type": media_type,
-                "media_length": length,
-                "download_name": download_name,
-                "created_ts": time_now_ms,
-                "filesystem_id": file_id,
-                "filename": fname,
-                "uri": uri,
-                "response_code": code,
-                # FIXME: we should calculate a proper expiration based on the
-                # Cache-Control and Expire headers.  But for now, assume 1 hour.
-                "expires": 60 * 60 * 1000,
-                "etag": headers["ETag"][0] if "ETag" in headers else None,
-            }
-        )
+        return {
+            "media_type": media_type,
+            "media_length": length,
+            "download_name": download_name,
+            "created_ts": time_now_ms,
+            "filesystem_id": file_id,
+            "filename": fname,
+            "uri": uri,
+            "response_code": code,
+            # FIXME: we should calculate a proper expiration based on the
+            # Cache-Control and Expire headers.  But for now, assume 1 hour.
+            "expires": 60 * 60 * 1000,
+            "etag": headers["ETag"][0] if "ETag" in headers else None,
+        }
 
     def _start_expire_url_cache_data(self):
         return run_as_background_process(