3 files changed, 10 insertions, 10 deletions
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index 0ac85a3be7..7d04560dca 100644
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -884,7 +884,7 @@ class FederationClient(FederationBase):
                 if 500 <= e.code < 600:
                     failover = True
 
-                elif e.code == 400 and synapse_error.errcode in failover_errcodes:
+                elif 400 <= e.code < 500 and synapse_error.errcode in failover_errcodes:
                     failover = True
 
                 elif failover_on_unknown_endpoint and self._is_unknown_endpoint(
@@ -999,14 +999,13 @@ class FederationClient(FederationBase):
 
             return destination, ev, room_version
 
+        failover_errcodes = {Codes.NOT_FOUND}
         # MSC3083 defines additional error codes for room joins. Unfortunately
         # we do not yet know the room version, assume these will only be returned
         # by valid room versions.
-        failover_errcodes = (
-            (Codes.UNABLE_AUTHORISE_JOIN, Codes.UNABLE_TO_GRANT_JOIN)
-            if membership == Membership.JOIN
-            else None
-        )
+        if membership == Membership.JOIN:
+            failover_errcodes.add(Codes.UNABLE_AUTHORISE_JOIN)
+            failover_errcodes.add(Codes.UNABLE_TO_GRANT_JOIN)
 
         return await self._try_destination_list(
             "make_" + membership,
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 3b115bacdd..86cd2c87f1 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -23,6 +23,7 @@ from typing import (
     Collection,
     Dict,
     List,
+    Mapping,
     Optional,
     Tuple,
     Union,
@@ -47,6 +48,7 @@ from synapse.api.errors import (
     FederationError,
     IncompatibleRoomVersionError,
     NotFoundError,
+    PartialStateConflictError,
     SynapseError,
     UnsupportedRoomVersionError,
 )
@@ -80,7 +82,6 @@ from synapse.replication.http.federation import (
     ReplicationFederationSendEduRestServlet,
     ReplicationGetQueryRestServlet,
 )
-from synapse.storage.databases.main.events import PartialStateConflictError
 from synapse.storage.databases.main.lock import Lock
 from synapse.storage.databases.main.roommember import extract_heroes_from_room_summary
 from synapse.storage.roommember import MemberSummary
@@ -1512,7 +1513,7 @@ class FederationHandlerRegistry:
 def _get_event_ids_for_partial_state_join(
     join_event: EventBase,
     prev_state_ids: StateMap[str],
-    summary: Dict[str, MemberSummary],
+    summary: Mapping[str, MemberSummary],
 ) -> Collection[str]:
     """Calculate state to be returned in a partial_state send_join
 
diff --git a/synapse/federation/send_queue.py b/synapse/federation/send_queue.py
index d720b5fd3f..3063df7990 100644
--- a/synapse/federation/send_queue.py
+++ b/synapse/federation/send_queue.py
@@ -314,7 +314,7 @@ class FederationRemoteSendQueue(AbstractFederationSender):
         # stream position.
         keyed_edus = {v: k for k, v in self.keyed_edu_changed.items()[i:j]}
 
-        for ((destination, edu_key), pos) in keyed_edus.items():
+        for (destination, edu_key), pos in keyed_edus.items():
             rows.append(
                 (
                     pos,
@@ -329,7 +329,7 @@ class FederationRemoteSendQueue(AbstractFederationSender):
         j = self.edus.bisect_right(to_token) + 1
         edus = self.edus.items()[i:j]
 
-        for (pos, edu) in edus:
+        for pos, edu in edus:
             rows.append((pos, EduRow(edu)))
 
         # Sort rows based on pos