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synapse/handlers/sync.py

@@ -289,9 +289,9 @@ class SyncResult:
 class E2eeSyncResult:
     next_batch: StreamToken
     to_device: List[JsonDict]
-    # device_lists: DeviceListUpdates
+    device_lists: DeviceListUpdates
-    # device_one_time_keys_count: JsonMapping
+    device_one_time_keys_count: JsonMapping
-    # device_unused_fallback_key_types: List[str]
+    device_unused_fallback_key_types: List[str]
 
 
 class SyncHandler:
@@ -1813,19 +1813,46 @@ class SyncHandler:
             full_state=False,
         )
 
-        # 1. Calculate `device_lists`
+        # 1. Calculate `to_device` events
-        device_lists = await self._generate_sync_entry_for_device_list(
-            sync_result_builder
-        )
-
-        # 2. Calculate `to_device` events
         await self._generate_sync_entry_for_to_device(sync_result_builder)
 
+        # 2. Calculate `device_lists`
+        # Device list updates are sent if a since token is provided.
+        device_lists = DeviceListUpdates()
+        include_device_list_updates = bool(since_token and since_token.device_list_key)
+        if include_device_list_updates:
+            device_lists = await self._generate_sync_entry_for_device_list(
+                sync_result_builder,
+                # TODO: Do we need to worry about these? All of this info is
+                # normally calculated when we `_generate_sync_entry_for_rooms()` but we
+                # probably don't want to do all of that work for this endpoint.
+                newly_joined_rooms=frozenset(),
+                newly_joined_or_invited_or_knocked_users=frozenset(),
+                newly_left_rooms=frozenset(),
+                newly_left_users=frozenset(),
+            )
+
+        # 3. Calculate `device_one_time_keys_count` and `device_unused_fallback_key_types`
+        device_id = sync_config.device_id
+        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:
+            #   * no change in OTK count since the provided since token
+            #   * the server has zero OTKs left for this device
+            #  Spec issue: https://github.com/matrix-org/matrix-doc/issues/3298
+            one_time_keys_count = await self.store.count_e2e_one_time_keys(
+                user_id, device_id
+            )
+            unused_fallback_key_types = list(
+                await self.store.get_e2e_unused_fallback_key_types(user_id, device_id)
+            )
+
         return E2eeSyncResult(
             to_device=sync_result_builder.to_device,
             device_lists=device_lists,
-            # device_one_time_keys_count: JsonMapping
+            device_one_time_keys_count=one_time_keys_count,
-            # device_unused_fallback_key_types: List[str]
+            device_unused_fallback_key_types=unused_fallback_key_types,
             next_batch=sync_result_builder.now_token,
         )
 
@@ -2007,7 +2034,7 @@ class SyncHandler:
 
         users_that_have_changed = set()
 
-        joined_rooms = sync_result_builder.joined_room_ids
+        joined_room_ids = sync_result_builder.joined_room_ids
 
         # Step 1a, check for changes in devices of users we share a room
         # with
@@ -2032,14 +2059,14 @@ class SyncHandler:
                 # or if the changed user is the syncing user (as we always
                 # want to include device list updates of their own devices).
                 if user_id == changed_user_id or any(
-                    rid in joined_rooms for rid in entries
+                    rid in joined_room_ids for rid in entries
                 ):
                     users_that_have_changed.add(changed_user_id)
         else:
             users_that_have_changed = (
                 await self._device_handler.get_device_changes_in_shared_rooms(
                     user_id,
-                    sync_result_builder.joined_room_ids,
+                    joined_room_ids,
                     from_token=since_token,
                 )
             )
@@ -2066,7 +2093,7 @@ class SyncHandler:
         # Remove any users that we still share a room with.
         left_users_rooms = await self.store.get_rooms_for_users(newly_left_users)
         for user_id, entries in left_users_rooms.items():
-            if any(rid in joined_rooms for rid in entries):
+            if any(rid in joined_room_ids for rid in entries):
                 newly_left_users.discard(user_id)
 
         return DeviceListUpdates(changed=users_that_have_changed, left=newly_left_users)

synapse/rest/client/sync.py

@@ -624,9 +624,11 @@ class SlidingSyncE2eeRestServlet(RestServlet):
         if since is not None:
             since_token = await StreamToken.from_string(self.store, since)
 
+        logger.info(f"sync with since_token: {since_token}")
+
         # Request cache key
         request_key = (
-            SyncVersion.SYNC_V2,
+            SyncVersion.E2EE_SYNC,
             user,
             timeout,
             since,
@@ -636,7 +638,7 @@ class SlidingSyncE2eeRestServlet(RestServlet):
         sync_result = await self.sync_handler.wait_for_sync_for_user(
             requester,
             sync_config,
-            SyncVersion.SYNC_V2,
+            SyncVersion.E2EE_SYNC,
             request_key,
             since_token=since_token,
             timeout=timeout,
@@ -655,6 +657,24 @@ class SlidingSyncE2eeRestServlet(RestServlet):
         if sync_result.to_device:
             response["to_device"] = {"events": sync_result.to_device}
 
+        if sync_result.device_lists.changed:
+            response["device_lists"]["changed"] = list(sync_result.device_lists.changed)
+        if sync_result.device_lists.left:
+            response["device_lists"]["left"] = list(sync_result.device_lists.left)
+
+        # We always include this because https://github.com/vector-im/element-android/issues/3725
+        # The spec isn't terribly clear on when this can be omitted and how a client would tell
+        # the difference between "no keys present" and "nothing changed" in terms of whole field
+        # absent / individual key type entry absent
+        # Corresponding synapse issue: https://github.com/matrix-org/synapse/issues/10456
+        response["device_one_time_keys_count"] = sync_result.device_one_time_keys_count
+
+        # https://github.com/matrix-org/matrix-doc/blob/54255851f642f84a4f1aaf7bc063eebe3d76752b/proposals/2732-olm-fallback-keys.md
+        # states that this field should always be included, as long as the server supports the feature.
+        response["device_unused_fallback_key_types"] = (
+            sync_result.device_unused_fallback_key_types
+        )
+
         return 200, response