fix: update state_cache on join over federation

src/api/client_server/membership.rs

@@ -669,24 +669,21 @@ async fn join_room_by_id_helper(
                 .add_pdu_outlier(&event_id, &value)?;
         }
 
-        let statehash_before_join = services().rooms.state.set_event_state(
-            event_id,
+        let (statehash_before_join, new, removed) = services().rooms.state_compressor.save_state(
             room_id,
             state
                 .into_iter()
-                .map(|(k, id)| {
-                    services()
-                        .rooms
-                        .state_compressor
-                        .compress_state_event(k, &id)
-                })
+                .map(|(k, id)| services().rooms.state_compressor.compress_state_event(k, &id))
                 .collect::<Result<_>>()?,
         )?;
 
         services()
             .rooms
             .state
-            .set_room_state(room_id, statehash_before_join, &state_lock)?;
+            .force_state(room_id, statehash_before_join, new, removed, &state_lock)
+            .await?;
+
+        services().rooms.state_cache.update_joined_count(room_id)?;
 
         // We append to state before appending the pdu, so we don't have a moment in time with the
         // pdu without it's state. This is okay because append_pdu can't fail.

src/database/key_value/rooms/state_accessor.rs

@@ -23,7 +23,7 @@ impl service::rooms::state_accessor::Data for KeyValueDatabase {
             let parsed = services()
                 .rooms
                 .state_compressor
-                .parse_compressed_state_event(compressed)?;
+                .parse_compressed_state_event(&compressed)?;
             result.insert(parsed.0, parsed.1);
 
             i += 1;
@@ -52,7 +52,7 @@ impl service::rooms::state_accessor::Data for KeyValueDatabase {
             let (_, eventid) = services()
                 .rooms
                 .state_compressor
-                .parse_compressed_state_event(compressed)?;
+                .parse_compressed_state_event(&compressed)?;
             if let Some(pdu) = services().rooms.timeline.get_pdu(&eventid)? {
                 result.insert(
                     (
@@ -104,7 +104,7 @@ impl service::rooms::state_accessor::Data for KeyValueDatabase {
                 services()
                     .rooms
                     .state_compressor
-                    .parse_compressed_state_event(compressed)
+                    .parse_compressed_state_event(&compressed)
                     .ok()
                     .map(|(_, id)| id)
             }))

src/service/rooms/event_handler/mod.rs

@@ -970,14 +970,11 @@ impl Service {
             // Set the new room state to the resolved state
             if update_state {
                 info!("Forcing new room state");
-                let sstatehash = services()
+                let (sstatehash, new, removed) = services()
                     .rooms
                     .state_compressor
                     .save_state(room_id, new_room_state)?;
-                services()
-                    .rooms
-                    .state
-                    .set_room_state(room_id, sstatehash, &state_lock)?;
+                services().rooms.state.force_state(room_id, sstatehash, new, removed, &state_lock).await?;
             }
         }
 

src/service/rooms/state/data.rs

@@ -8,7 +8,7 @@ pub trait Data: Send + Sync {
     /// Returns the last state hash key added to the db for the given room.
     fn get_room_shortstatehash(&self, room_id: &RoomId) -> Result<Option<u64>>;
 
-    /// Update the current state of the room.
+    /// Set the state hash to a new version, but does not update state_cache.
     fn set_room_state(
         &self,
         room_id: &RoomId,

src/service/rooms/state/mod.rs

@@ -34,23 +34,13 @@ impl Service {
         shortstatehash: u64,
         statediffnew: HashSet<CompressedStateEvent>,
         _statediffremoved: HashSet<CompressedStateEvent>,
+        state_lock: &MutexGuard<'_, ()>, // Take mutex guard to make sure users get the room state mutex
     ) -> Result<()> {
-        let mutex_state = Arc::clone(
-            services()
-                .globals
-                .roomid_mutex_state
-                .write()
-                .unwrap()
-                .entry(room_id.to_owned())
-                .or_default(),
-        );
-        let state_lock = mutex_state.lock().await;
-
         for event_id in statediffnew.into_iter().filter_map(|new| {
             services()
                 .rooms
                 .state_compressor
-                .parse_compressed_state_event(new)
+                .parse_compressed_state_event(&new)
                 .ok()
                 .map(|(_, id)| id)
         }) {
@@ -105,8 +95,6 @@ impl Service {
         self.db
             .set_room_state(room_id, shortstatehash, &state_lock)?;
 
-        drop(state_lock);
-
         Ok(())
     }
 
@@ -312,6 +300,7 @@ impl Service {
         Ok(state)
     }
 
+    /// Set the state hash to a new version, but does not update state_cache.
     #[tracing::instrument(skip(self))]
     pub fn set_room_state(
         &self,
@@ -412,7 +401,7 @@ impl Service {
                 services()
                     .rooms
                     .state_compressor
-                    .parse_compressed_state_event(compressed)
+                    .parse_compressed_state_event(&compressed)
                     .ok()
             })
             .filter_map(|(shortstatekey, event_id)| {

src/service/rooms/state_compressor/mod.rs

@@ -100,7 +100,7 @@ impl Service {
     /// Returns shortstatekey, event id
     pub fn parse_compressed_state_event(
         &self,
-        compressed_event: CompressedStateEvent,
+        compressed_event: &CompressedStateEvent,
     ) -> Result<(u64, Arc<EventId>)> {
         Ok((
             utils::u64_from_bytes(&compressed_event[0..size_of::<u64>()])
@@ -246,12 +246,12 @@ impl Service {
         Ok(())
     }
 
-    /// Returns the new shortstatehash
+    /// Returns the new shortstatehash, and the state diff from the previous room state
     pub fn save_state(
         &self,
         room_id: &RoomId,
         new_state_ids_compressed: HashSet<CompressedStateEvent>,
-    ) -> Result<u64> {
+    ) -> Result<(u64, HashSet<CompressedStateEvent>, HashSet<CompressedStateEvent>)> {
         let previous_shortstatehash = services().rooms.state.get_room_shortstatehash(room_id)?;
 
         let state_hash = utils::calculate_hash(
@@ -267,7 +267,7 @@ impl Service {
             .get_or_create_shortstatehash(&state_hash)?;
 
         if Some(new_shortstatehash) == previous_shortstatehash {
-            return Ok(new_shortstatehash);
+            return Ok((new_shortstatehash, HashSet::new(), HashSet::new()));
         }
 
         let states_parents = previous_shortstatehash
@@ -295,12 +295,12 @@ impl Service {
             self.save_state_from_diff(
                 new_shortstatehash,
                 statediffnew.clone(),
-                statediffremoved,
+                statediffremoved.clone(),
                 2, // every state change is 2 event changes on average
                 states_parents,
             )?;
         };
 
-        Ok(new_shortstatehash)
+        Ok((new_shortstatehash, statediffnew, statediffremoved))
     }
 }