From 8586d747d12cb32cd9caec5cae2058691070cb87 Mon Sep 17 00:00:00 2001
From: Jade Ellis <jade@ellis.link>
Date: Thu, 18 Dec 2025 23:19:13 +0000
Subject: [PATCH] feat: Run visibility checks on bundled relations

---
 src/api/client/threads.rs                     |  2 --
 .../pdu_metadata/bundled_aggregations.rs      | 35 +++++++++++++------
 src/service/rooms/pdu_metadata/mod.rs         |  3 ++
 3 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/src/api/client/threads.rs b/src/api/client/threads.rs
index 32da2adb..86c3a399 100644
--- a/src/api/client/threads.rs
+++ b/src/api/client/threads.rs
@@ -31,8 +31,6 @@ pub(crate) async fn get_threads_route(
 		.transpose()?
 		.unwrap_or_else(PduCount::max);
 
-	// TODO: user_can_see_event and set_unsigned should be at the same level /
-	// function, so unsigned is only set for seen events.
 	let threads: Vec<(PduCount, PduEvent)> = services
 		.rooms
 		.threads
diff --git a/src/service/rooms/pdu_metadata/bundled_aggregations.rs b/src/service/rooms/pdu_metadata/bundled_aggregations.rs
index 53c651ac..cf780df5 100644
--- a/src/service/rooms/pdu_metadata/bundled_aggregations.rs
+++ b/src/service/rooms/pdu_metadata/bundled_aggregations.rs
@@ -41,9 +41,6 @@ impl super::Service {
 		// The relations database code still handles the basic unsigned data
 		// We don't want to recursively fetch relations
 
-		// TODO: Event visibility check
-		// TODO: ignored users?
-
 		if relations.is_empty() {
 			return Ok(None);
 		}
@@ -84,8 +81,17 @@ impl super::Service {
 		// Handle m.replace relations - find the most recent valid one (lazy load
 		// original event)
 		if !replace_events.is_empty() {
-			if let Some(replacement) =
-				Self::find_most_recent_valid_replacement(pdu, &replace_events).await?
+			if let Some(replacement) = Self::find_most_recent_valid_replacement(
+				pdu,
+				&replace_events,
+				async |pdu: &PduEvent| {
+					self.services
+						.state_accessor
+						.user_can_see_event(user_id, &pdu.room_id_or_hash(), &pdu.event_id())
+						.await
+				},
+			)
+			.await?
 			{
 				bundled.replace = Some(Self::serialize_replacement(replacement)?);
 			}
@@ -124,6 +130,7 @@ impl super::Service {
 	async fn find_most_recent_valid_replacement<'a>(
 		original_event: &PduEvent,
 		replacement_events: &[&'a PdusIterItem],
+		visible: impl AsyncFn(&PduEvent) -> bool,
 	) -> Result<Option<&'a PduEvent>> {
 		// Filter valid replacements and find the maximum in a single pass
 		let mut result: Option<&PduEvent> = None;
@@ -136,17 +143,23 @@ impl super::Service {
 				continue;
 			}
 
-			result = Some(match result {
-				| None => pdu,
+			let next = match result {
+				| None => Some(pdu),
 				| Some(current) => {
 					// Compare by origin_server_ts first, then event_id lexicographically
 					match pdu.origin_server_ts().cmp(&current.origin_server_ts()) {
-						| std::cmp::Ordering::Greater => pdu,
-						| std::cmp::Ordering::Equal if pdu.event_id() > current.event_id() => pdu,
-						| _ => current,
+						| std::cmp::Ordering::Greater => Some(pdu),
+						| std::cmp::Ordering::Equal if pdu.event_id() > current.event_id() =>
+							Some(pdu),
+						| _ => None,
 					}
 				},
-			});
+			};
+			if let Some(pdu) = next
+				&& visible(pdu).await
+			{
+				result = Some(pdu);
+			}
 		}
 
 		Ok(result)
diff --git a/src/service/rooms/pdu_metadata/mod.rs b/src/service/rooms/pdu_metadata/mod.rs
index e1f351a3..9bbc7c9c 100644
--- a/src/service/rooms/pdu_metadata/mod.rs
+++ b/src/service/rooms/pdu_metadata/mod.rs
@@ -20,6 +20,7 @@ pub struct Service {
 struct Services {
 	short: Dep<rooms::short::Service>,
 	timeline: Dep<rooms::timeline::Service>,
+	state_accessor: Dep<rooms::state_accessor::Service>,
 }
 
 impl crate::Service for Service {
@@ -28,6 +29,8 @@ impl crate::Service for Service {
 			services: Services {
 				short: args.depend::<rooms::short::Service>("rooms::short"),
 				timeline: args.depend::<rooms::timeline::Service>("rooms::timeline"),
+				state_accessor: args
+					.depend::<rooms::state_accessor::Service>("rooms::state_accessor"),
 			},
 			db: Data::new(&args),
 		}))