impl MSC3706

Cargo.toml

@@ -328,7 +328,7 @@ default-features = false
 
 [workspace.dependencies.ruma]
 git = "https://github.com/matrix-construct/ruma"
-rev = "d4b779ab8abb416e2ddc2fc7f322ed86bd4b5648"
+rev = "8564227896ed0f20f46eb4d717b7061f4ddd17ae"
 features = [
     "__compat",
     "appservice-api-c",

docker/Dockerfile.complement

@@ -130,7 +130,7 @@ ENTRYPOINT valgrind \
 FROM input AS complement-base
 ARG var_cache
 ARG var_lib_apt
-ARG complement_ref="5ca17e228083b44a38aeed3398ecc94529ae696e"
+ARG complement_ref="97a724b5431b4f4086fe71db0901615ae6ab1ae9"
 ARG complement_tags="conduwuit_blacklist"
 ARG complement_tests="./tests/..."
 ARG complement_run=".*"

src/api/client/sync/mod.rs

@@ -10,7 +10,10 @@ use tuwunel_core::{
 };
 use tuwunel_service::Services;
 
-pub(crate) use self::{v3::sync_events_route, v5::sync_events_v5_route};
+pub(crate) use self::{
+	v3::{calculate_heroes, sync_events_route},
+	v5::sync_events_v5_route,
+};
 
 async fn load_timeline(
 	services: &Services,

src/api/client/sync/v3.rs

@@ -1305,47 +1305,42 @@ async fn calculate_counts(
 	(Some(joined_member_count), Some(invited_member_count), heroes.await)
 }
 
-async fn calculate_heroes(
+pub(crate) async fn calculate_heroes(
 	services: &Services,
 	room_id: &RoomId,
 	sender_user: &UserId,
 ) -> Vec<OwnedUserId> {
+	const LIMIT: usize = 5;
+
 	services
 		.state_accessor
 		.room_state_type_pdus(room_id, &StateEventType::RoomMember)
 		.ready_filter_map(Result::ok)
-		.fold_default(|heroes: Vec<_>, pdu| {
-			fold_hero(heroes, services, room_id, sender_user, pdu)
-		})
+		.filter_map(|pdu| filter_hero(services, room_id, sender_user, pdu))
+		.take(LIMIT)
+		.collect::<Vec<_>>()
 		.await
 }
 
-async fn fold_hero<Pdu: Event>(
-	mut heroes: Vec<OwnedUserId>,
+async fn filter_hero<Pdu: Event>(
 	services: &Services,
 	room_id: &RoomId,
 	sender_user: &UserId,
 	pdu: Pdu,
-) -> Vec<OwnedUserId> {
-	let Some(user_id): Option<&UserId> = pdu.state_key().map(TryInto::try_into).flat_ok() else {
-		return heroes;
-	};
+) -> Option<OwnedUserId> {
+	let user_id = pdu.state_key().map(TryInto::try_into).flat_ok()?;
 
 	if user_id == sender_user {
-		return heroes;
+		return None;
 	}
 
 	let Ok(content): Result<RoomMemberEventContent, _> = pdu.get_content() else {
-		return heroes;
+		return None;
 	};
 
 	// The membership was and still is invite or join
 	if !matches!(content.membership, MembershipState::Join | MembershipState::Invite) {
-		return heroes;
-	}
-
-	if heroes.iter().any(is_equal_to!(user_id)) {
-		return heroes;
+		return None;
 	}
 
 	let (is_invited, is_joined) = join(
@@ -1355,11 +1350,10 @@ async fn fold_hero<Pdu: Event>(
 	.await;
 
 	if !is_joined && is_invited {
-		return heroes;
+		return None;
 	}
 
-	heroes.push(user_id.to_owned());
-	heroes
+	Some(user_id.to_owned())
 }
 
 async fn typings_event_for_user(