Return immutable objects for cachedList decorators (#16350)

6 files changed, 37 insertions, 33 deletions

diff --git a/synapse/handlers/appservice.py b/synapse/handlers/appservice.py
index 6429545c98..7de7bd3289 100644
--- a/synapse/handlers/appservice.py
+++ b/synapse/handlers/appservice.py
@@ -46,6 +46,7 @@ from synapse.storage.databases.main.directory import RoomAliasMapping
 from synapse.types import (
     DeviceListUpdates,
     JsonDict,
+    JsonMapping,
     RoomAlias,
     RoomStreamToken,
     StreamKeyType,
@@ -397,7 +398,7 @@ class ApplicationServicesHandler:
 
     async def _handle_typing(
         self, service: ApplicationService, new_token: int
-    ) -> List[JsonDict]:
+    ) -> List[JsonMapping]:
         """
         Return the typing events since the given stream token that the given application
         service should receive.
@@ -432,7 +433,7 @@ class ApplicationServicesHandler:
 
     async def _handle_receipts(
         self, service: ApplicationService, new_token: int
-    ) -> List[JsonDict]:
+    ) -> List[JsonMapping]:
         """
         Return the latest read receipts that the given application service should receive.
 
@@ -471,7 +472,7 @@ class ApplicationServicesHandler:
         service: ApplicationService,
         users: Collection[Union[str, UserID]],
         new_token: Optional[int],
-    ) -> List[JsonDict]:
+    ) -> List[JsonMapping]:
         """
         Return the latest presence updates that the given application service should receive.
 
@@ -491,7 +492,7 @@ class ApplicationServicesHandler:
             A list of json dictionaries containing data derived from the presence events
             that should be sent to the given application service.
         """
-        events: List[JsonDict] = []
+        events: List[JsonMapping] = []
         presence_source = self.event_sources.sources.presence
         from_key = await self.store.get_type_stream_id_for_appservice(
             service, "presence"
diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
index ad075497c8..8c6432035d 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -14,7 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-from typing import TYPE_CHECKING, Any, Dict, Iterable, List, Mapping, Optional, Tuple
+from typing import TYPE_CHECKING, Dict, Iterable, List, Mapping, Optional, Tuple
 
 import attr
 from canonicaljson import encode_canonical_json
@@ -31,6 +31,7 @@ from synapse.logging.context import make_deferred_yieldable, run_in_background
 from synapse.logging.opentracing import log_kv, set_tag, tag_args, trace
 from synapse.types import (
     JsonDict,
+    JsonMapping,
     UserID,
     get_domain_from_id,
     get_verify_key_from_cross_signing_key,
@@ -272,11 +273,7 @@ class E2eKeysHandler:
                 delay_cancellation=True,
             )
 
-            ret = {"device_keys": results, "failures": failures}
-
-            ret.update(cross_signing_keys)
-
-            return ret
+            return {"device_keys": results, "failures": failures, **cross_signing_keys}
 
     @trace
     async def _query_devices_for_destination(
@@ -408,7 +405,7 @@ class E2eKeysHandler:
     @cancellable
     async def get_cross_signing_keys_from_cache(
         self, query: Iterable[str], from_user_id: Optional[str]
-    ) -> Dict[str, Dict[str, dict]]:
+    ) -> Dict[str, Dict[str, JsonMapping]]:
         """Get cross-signing keys for users from the database
 
         Args:
@@ -551,16 +548,13 @@ class E2eKeysHandler:
                 self.config.federation.allow_device_name_lookup_over_federation
             ),
         )
-        ret = {"device_keys": res}
 
         # add in the cross-signing keys
         cross_signing_keys = await self.get_cross_signing_keys_from_cache(
             device_keys_query, None
         )
 
-        ret.update(cross_signing_keys)
-
-        return ret
+        return {"device_keys": res, **cross_signing_keys}
 
     async def claim_local_one_time_keys(
         self,
@@ -1127,7 +1121,7 @@ class E2eKeysHandler:
         user_id: str,
         master_key_id: str,
         signed_master_key: JsonDict,
-        stored_master_key: JsonDict,
+        stored_master_key: JsonMapping,
         devices: Dict[str, Dict[str, JsonDict]],
     ) -> List["SignatureListItem"]:
         """Check signatures of a user's master key made by their devices.
@@ -1278,7 +1272,7 @@ class E2eKeysHandler:
 
     async def _get_e2e_cross_signing_verify_key(
         self, user_id: str, key_type: str, from_user_id: Optional[str] = None
-    ) -> Tuple[JsonDict, str, VerifyKey]:
+    ) -> Tuple[JsonMapping, str, VerifyKey]:
         """Fetch locally or remotely query for a cross-signing public key.
 
         First, attempt to fetch the cross-signing public key from storage.
@@ -1333,7 +1327,7 @@ class E2eKeysHandler:
         self,
         user: UserID,
         desired_key_type: str,
-    ) -> Optional[Tuple[Dict[str, Any], str, VerifyKey]]:
+    ) -> Optional[Tuple[JsonMapping, str, VerifyKey]]:
         """Queries cross-signing keys for a remote user and saves them to the database
 
         Only the key specified by `key_type` will be returned, while all retrieved keys
@@ -1474,7 +1468,7 @@ def _check_device_signature(
     user_id: str,
     verify_key: VerifyKey,
     signed_device: JsonDict,
-    stored_device: JsonDict,
+    stored_device: JsonMapping,
 ) -> None:
     """Check that a signature on a device or cross-signing key is correct and
     matches the copy of the device/key that we have stored.  Throws an
diff --git a/synapse/handlers/initial_sync.py b/synapse/handlers/initial_sync.py
index 5dc76ef588..5737f8014d 100644
--- a/synapse/handlers/initial_sync.py
+++ b/synapse/handlers/initial_sync.py
@@ -32,6 +32,7 @@ from synapse.storage.roommember import RoomsForUser
 from synapse.streams.config import PaginationConfig
 from synapse.types import (
     JsonDict,
+    JsonMapping,
     Requester,
     RoomStreamToken,
     StreamKeyType,
@@ -454,7 +455,7 @@ class InitialSyncHandler:
                 for s in states
             ]
 
-        async def get_receipts() -> List[JsonDict]:
+        async def get_receipts() -> List[JsonMapping]:
             receipts = await self.store.get_linearized_receipts_for_room(
                 room_id, to_key=now_token.receipt_key
             )
diff --git a/synapse/handlers/receipts.py b/synapse/handlers/receipts.py
index c7edada353..a7a29b758b 100644
--- a/synapse/handlers/receipts.py
+++ b/synapse/handlers/receipts.py
@@ -19,6 +19,7 @@ from synapse.appservice import ApplicationService
 from synapse.streams import EventSource
 from synapse.types import (
     JsonDict,
+    JsonMapping,
     ReadReceipt,
     StreamKeyType,
     UserID,
@@ -204,15 +205,15 @@ class ReceiptsHandler:
             await self.federation_sender.send_read_receipt(receipt)
 
 
-class ReceiptEventSource(EventSource[int, JsonDict]):
+class ReceiptEventSource(EventSource[int, JsonMapping]):
     def __init__(self, hs: "HomeServer"):
         self.store = hs.get_datastores().main
         self.config = hs.config
 
     @staticmethod
     def filter_out_private_receipts(
-        rooms: Sequence[JsonDict], user_id: str
-    ) -> List[JsonDict]:
+        rooms: Sequence[JsonMapping], user_id: str
+    ) -> List[JsonMapping]:
         """
         Filters a list of serialized receipts (as returned by /sync and /initialSync)
         and removes private read receipts of other users.
@@ -229,7 +230,7 @@ class ReceiptEventSource(EventSource[int, JsonDict]):
             The same as rooms, but filtered.
         """
 
-        result = []
+        result: List[JsonMapping] = []
 
         # Iterate through each room's receipt content.
         for room in rooms:
@@ -282,7 +283,7 @@ class ReceiptEventSource(EventSource[int, JsonDict]):
         room_ids: Iterable[str],
         is_guest: bool,
         explicit_room_id: Optional[str] = None,
-    ) -> Tuple[List[JsonDict], int]:
+    ) -> Tuple[List[JsonMapping], int]:
         from_key = int(from_key)
         to_key = self.get_current_key()
 
@@ -301,7 +302,7 @@ class ReceiptEventSource(EventSource[int, JsonDict]):
 
     async def get_new_events_as(
         self, from_key: int, to_key: int, service: ApplicationService
-    ) -> Tuple[List[JsonDict], int]:
+    ) -> Tuple[List[JsonMapping], int]:
         """Returns a set of new read receipt events that an appservice
         may be interested in.
 
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 1a4d394eda..7bd42f635f 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -235,7 +235,7 @@ class SyncResult:
     archived: List[ArchivedSyncResult]
     to_device: List[JsonDict]
     device_lists: DeviceListUpdates
-    device_one_time_keys_count: JsonDict
+    device_one_time_keys_count: JsonMapping
     device_unused_fallback_key_types: List[str]
 
     def __bool__(self) -> bool:
@@ -1558,7 +1558,7 @@ class SyncHandler:
 
         logger.debug("Fetching OTK data")
         device_id = sync_config.device_id
-        one_time_keys_count: JsonDict = {}
+        one_time_keys_count: JsonMapping = {}
         unused_fallback_key_types: List[str] = []
         if device_id:
             # TODO: We should have a way to let clients differentiate between the states of:
diff --git a/synapse/handlers/typing.py b/synapse/handlers/typing.py
index 4b4227003d..bdefa7f26f 100644
--- a/synapse/handlers/typing.py
+++ b/synapse/handlers/typing.py
@@ -26,7 +26,14 @@ from synapse.metrics.background_process_metrics import (
 )
 from synapse.replication.tcp.streams import TypingStream
 from synapse.streams import EventSource
-from synapse.types import JsonDict, Requester, StrCollection, StreamKeyType, UserID
+from synapse.types import (
+    JsonDict,
+    JsonMapping,
+    Requester,
+    StrCollection,
+    StreamKeyType,
+    UserID,
+)
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 from synapse.util.metrics import Measure
 from synapse.util.retryutils import filter_destinations_by_retry_limiter
@@ -487,7 +494,7 @@ class TypingWriterHandler(FollowerTypingHandler):
         raise Exception("Typing writer instance got typing info over replication")
 
 
-class TypingNotificationEventSource(EventSource[int, JsonDict]):
+class TypingNotificationEventSource(EventSource[int, JsonMapping]):
     def __init__(self, hs: "HomeServer"):
         self._main_store = hs.get_datastores().main
         self.clock = hs.get_clock()
@@ -497,7 +504,7 @@ class TypingNotificationEventSource(EventSource[int, JsonDict]):
         #
         self.get_typing_handler = hs.get_typing_handler
 
-    def _make_event_for(self, room_id: str) -> JsonDict:
+    def _make_event_for(self, room_id: str) -> JsonMapping:
         typing = self.get_typing_handler()._room_typing[room_id]
         return {
             "type": EduTypes.TYPING,
@@ -507,7 +514,7 @@ class TypingNotificationEventSource(EventSource[int, JsonDict]):
 
     async def get_new_events_as(
         self, from_key: int, service: ApplicationService
-    ) -> Tuple[List[JsonDict], int]:
+    ) -> Tuple[List[JsonMapping], int]:
         """Returns a set of new typing events that an appservice
         may be interested in.
 
@@ -551,7 +558,7 @@ class TypingNotificationEventSource(EventSource[int, JsonDict]):
         room_ids: Iterable[str],
         is_guest: bool,
         explicit_room_id: Optional[str] = None,
-    ) -> Tuple[List[JsonDict], int]:
+    ) -> Tuple[List[JsonMapping], int]:
         with Measure(self.clock, "typing.get_new_events"):
             from_key = int(from_key)
             handler = self.get_typing_handler()