From c14f80c26f1e16fbc96cef1a724d35808c99c2d7 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Thu, 20 Jul 2023 09:34:22 +0100
Subject: [PATCH 1/2] Reduce the amount of state we pull out

---
 synapse/handlers/federation.py  |  6 ++----
 synapse/handlers/message.py     |  4 ++--
 synapse/handlers/room_member.py | 15 +++++++++------
 3 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 15b9fbe44a15..2b93b8c621c3 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -1581,9 +1581,7 @@ async def add_display_name_to_third_party_invite(
             event.content["third_party_invite"]["signed"]["token"],
         )
         original_invite = None
-        prev_state_ids = await context.get_prev_state_ids(
-            StateFilter.from_types([(EventTypes.ThirdPartyInvite, None)])
-        )
+        prev_state_ids = await context.get_prev_state_ids(StateFilter.from_types([key]))
         original_invite_id = prev_state_ids.get(key)
         if original_invite_id:
             original_invite = await self.store.get_event(
@@ -1636,7 +1634,7 @@ async def _check_signature(self, event: EventBase, context: EventContext) -> Non
         token = signed["token"]
 
         prev_state_ids = await context.get_prev_state_ids(
-            StateFilter.from_types([(EventTypes.ThirdPartyInvite, None)])
+            StateFilter.from_types([(EventTypes.ThirdPartyInvite, token)])
         )
         invite_event_id = prev_state_ids.get((EventTypes.ThirdPartyInvite, token))
 
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 4292b4703762..9910716bc61e 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -738,7 +738,7 @@ async def create_event(
                 prev_event_id = state_map.get((EventTypes.Member, event.sender))
             else:
                 prev_state_ids = await unpersisted_context.get_prev_state_ids(
-                    StateFilter.from_types([(EventTypes.Member, None)])
+                    StateFilter.from_types([(EventTypes.Member, event.sender)])
                 )
                 prev_event_id = prev_state_ids.get((EventTypes.Member, event.sender))
             prev_event = (
@@ -860,7 +860,7 @@ async def deduplicate_state_event(
             return None
 
         prev_state_ids = await context.get_prev_state_ids(
-            StateFilter.from_types([(event.type, None)])
+            StateFilter.from_types([(event.type, event.state_key)])
         )
         prev_event_id = prev_state_ids.get((event.type, event.state_key))
         if not prev_event_id:
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 82e4fa73636e..496e701f13d3 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -473,7 +473,7 @@ async def _local_membership_update(
                 )
                 context = await unpersisted_context.persist(event)
                 prev_state_ids = await context.get_prev_state_ids(
-                    StateFilter.from_types([(EventTypes.Member, None)])
+                    StateFilter.from_types([(EventTypes.Member, user_id)])
                 )
 
                 prev_member_event_id = prev_state_ids.get(
@@ -1340,7 +1340,7 @@ async def send_membership_event(
             requester = types.create_requester(target_user)
 
         prev_state_ids = await context.get_prev_state_ids(
-            StateFilter.from_types([(EventTypes.GuestAccess, None)])
+            StateFilter.from_types([(EventTypes.GuestAccess, "")])
         )
         if event.membership == Membership.JOIN:
             if requester.is_guest:
@@ -1362,11 +1362,14 @@ async def send_membership_event(
             ratelimit=ratelimit,
         )
 
-        prev_member_event_id = prev_state_ids.get(
-            (EventTypes.Member, event.state_key), None
-        )
-
         if event.membership == Membership.LEAVE:
+            prev_state_ids = await context.get_prev_state_ids(
+                StateFilter.from_types([(EventTypes.Member, event.state_key)])
+            )
+            prev_member_event_id = prev_state_ids.get(
+                (EventTypes.Member, event.state_key), None
+            )
+
             if prev_member_event_id:
                 prev_member_event = await self.store.get_event(prev_member_event_id)
                 if prev_member_event.membership == Membership.JOIN:

From 6e63d90303b776ac7477fd49111db49ecae379e4 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Thu, 20 Jul 2023 09:35:59 +0100
Subject: [PATCH 2/2] Newsfile

---
 changelog.d/15968.misc | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog.d/15968.misc

diff --git a/changelog.d/15968.misc b/changelog.d/15968.misc
new file mode 100644
index 000000000000..af7132cc72f6
--- /dev/null
+++ b/changelog.d/15968.misc
@@ -0,0 +1 @@
+Reduce the amount of state we pull out.