Handle remote device list updates during partial join (#13913)

c.f. #12993 (comment), point 3

This stores all device list updates that we receive while partial joins are ongoing, and processes them once we have the full state.

Note: We don't actually process the device lists in the same ways as if we weren't partially joined. Instead of updating the device list remote cache, we simply notify local users that a change in the remote user's devices has happened. I think this is safe as if the local user requests the keys for the remote user and we don't have them we'll simply fetch them as normal.

1 files changed, 28 insertions, 0 deletions

diff --git a/synapse/storage/schema/main/delta/73/04pending_device_list_updates.sql b/synapse/storage/schema/main/delta/73/04pending_device_list_updates.sql
new file mode 100644
index 0000000000..dbd78d677d
--- /dev/null
+++ b/synapse/storage/schema/main/delta/73/04pending_device_list_updates.sql
@@ -0,0 +1,28 @@
+/* Copyright 2022 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+-- Stores remote device lists we have received for remote users while a partial
+-- join is in progress.
+--
+-- This allows us to replay any device list updates if it turns out the remote
+-- user was in the partially joined room
+CREATE TABLE device_lists_remote_pending(
+    stream_id BIGINT PRIMARY KEY,
+    user_id TEXT NOT NULL,
+    device_id TEXT NOT NULL
+);
+
+-- We only keep the most recent update for a given user/device pair.
+CREATE UNIQUE INDEX device_lists_remote_pending_user_device_id ON device_lists_remote_pending(user_id, device_id);