From d2cc2fb19bc8ec79434c72c0fa4fa3254e60d81d Mon Sep 17 00:00:00 2001
From: Ginger <ginger@gingershaped.computer>
Date: Thu, 6 Nov 2025 10:02:02 -0500
Subject: [PATCH] fix(sync/v3): Stop ignoring leave cache deserialization
 failures

---
 src/api/client/membership/leave.rs   |  2 +-
 src/service/rooms/state_cache/mod.rs | 20 ++++----------------
 2 files changed, 5 insertions(+), 17 deletions(-)

diff --git a/src/api/client/membership/leave.rs b/src/api/client/membership/leave.rs
index b439182c..a1d82668 100644
--- a/src/api/client/membership/leave.rs
+++ b/src/api/client/membership/leave.rs
@@ -177,7 +177,7 @@ pub async fn leave_room(
 					.rooms
 					.state_cache
 					.left_state(user_id, room_id)
-					.await
+					.await?
 			},
 		}
 	};
diff --git a/src/service/rooms/state_cache/mod.rs b/src/service/rooms/state_cache/mod.rs
index eaf1aeae..b87dfbe9 100644
--- a/src/service/rooms/state_cache/mod.rs
+++ b/src/service/rooms/state_cache/mod.rs
@@ -430,16 +430,9 @@ pub async fn knock_state(
 
 #[implement(Service)]
 #[tracing::instrument(skip(self), level = "trace")]
-pub async fn left_state(&self, user_id: &UserId, room_id: &RoomId) -> Option<Pdu> {
+pub async fn left_state(&self, user_id: &UserId, room_id: &RoomId) -> Result<Option<Pdu>> {
 	let key = (user_id, room_id);
-	self.db
-		.userroomid_leftstate
-		.qry(&key)
-		.await
-		.deserialized()
-		// old databases may have garbage data as values in the `userroomid_leftstate` table from before
-		// the leave event was stored there. they still need to be included, so we return Ok(None) for deserialization failures.
-		.unwrap_or(None)
+	self.db.userroomid_leftstate.qry(&key).await.deserialized()
 }
 
 /// Returns an iterator over all rooms a user left.
@@ -458,13 +451,8 @@ pub fn rooms_left<'a>(
 		.stream_prefix(&prefix)
 		.ignore_err()
 		.map(|((_, room_id), state): KeyVal<'_>| (room_id.to_owned(), state))
-		.ready_filter_map(|(room_id, state)| {
-			// deserialization errors need to be ignored. see comment in `left_state`
-			match state.deserialize() {
-				| Ok(state) => Some((room_id, state)),
-				| Err(_) => Some((room_id, None)),
-			}
-		})
+		.map(|(room_id, state)| Ok((room_id, state.deserialize()?)))
+		.ignore_err()
 }
 
 #[implement(Service)]