From b37aa1643bf3c3ff76f5b1d468a0b23c2acf66cc Mon Sep 17 00:00:00 2001
From: Will Hunt <will@half-shot.uk>
Date: Thu, 29 Oct 2020 16:58:16 +0000
Subject: [PATCH] Tie together matches_user_in_member_list and
 get_users_in_room caches (#8676)

* Tie together matches_user_in_member_list and get_users_in_room

* changelog

* Remove type to fix mypy

* Add `on_invalidate` to the function signature in the hopes that may make things work well

* Remove **kwargs

* Update 8676.bugfix
---
 changelog.d/8676.bugfix        |  1 +
 synapse/appservice/__init__.py | 10 ++++++----
 2 files changed, 7 insertions(+), 4 deletions(-)
 create mode 100644 changelog.d/8676.bugfix

diff --git a/changelog.d/8676.bugfix b/changelog.d/8676.bugfix
new file mode 100644
index 000000000000..df16c7276181
--- /dev/null
+++ b/changelog.d/8676.bugfix
@@ -0,0 +1 @@
+Fix a bug where an appservice may not be forwarded events for a room it was recently invited to. Broken in v1.22.0.
diff --git a/synapse/appservice/__init__.py b/synapse/appservice/__init__.py
index 3862d9c08f38..f70841ae8613 100644
--- a/synapse/appservice/__init__.py
+++ b/synapse/appservice/__init__.py
@@ -19,7 +19,7 @@
 from synapse.api.constants import EventTypes
 from synapse.events import EventBase
 from synapse.types import GroupID, JsonDict, UserID, get_domain_from_id
-from synapse.util.caches.descriptors import cached
+from synapse.util.caches.descriptors import _CacheContext, cached
 
 if TYPE_CHECKING:
     from synapse.appservice.api import ApplicationServiceApi
@@ -164,9 +164,9 @@ async def _matches_user(
         does_match = await self.matches_user_in_member_list(event.room_id, store)
         return does_match
 
-    @cached(num_args=1)
+    @cached(num_args=1, cache_context=True)
     async def matches_user_in_member_list(
-        self, room_id: str, store: "DataStore"
+        self, room_id: str, store: "DataStore", cache_context: _CacheContext,
     ) -> bool:
         """Check if this service is interested a room based upon it's membership
 
@@ -177,7 +177,9 @@ async def matches_user_in_member_list(
         Returns:
             True if this service would like to know about this room.
         """
-        member_list = await store.get_users_in_room(room_id)
+        member_list = await store.get_users_in_room(
+            room_id, on_invalidate=cache_context.invalidate
+        )
 
         # check joined member events
         for user_id in member_list: