feat(sliding sync): also empty the list caches when expiring a session

crates/matrix-sdk/src/sliding_sync/cache.rs

@@ -12,6 +12,8 @@ use tracing::{trace, warn};
 use super::{FrozenSlidingSyncList, SlidingSync, SlidingSyncPositionMarkers};
 #[cfg(feature = "e2e-encryption")]
 use crate::sliding_sync::FrozenSlidingSyncPos;
+#[cfg(doc)]
+use crate::sliding_sync::SlidingSyncList;
 use crate::{sliding_sync::SlidingSyncListCachePolicy, Client, Result};
 
 /// Be careful: as this is used as a storage key; changing it requires migrating
@@ -142,7 +144,7 @@ pub(super) async fn restore_sliding_sync_list(
     Ok(None)
 }
 
-/// Fields restored during `restore_sliding_sync_state`.
+/// Fields restored during [`restore_sliding_sync_state`].
 #[derive(Default)]
 pub(super) struct RestoredFields {
     pub to_device_token: Option<String>,

crates/matrix-sdk/src/sliding_sync/list/mod.rs

@@ -211,7 +211,6 @@ impl SlidingSyncList {
     }
 
     /// Set the maximum number of rooms.
-    #[cfg(test)]
     pub(super) fn set_maximum_number_of_rooms(&self, maximum_number_of_rooms: Option<u32>) {
         self.inner.maximum_number_of_rooms.set(maximum_number_of_rooms);
     }

crates/matrix-sdk/src/sliding_sync/mod.rs

@@ -725,14 +725,29 @@ impl SlidingSync {
     pub async fn expire_session(&self) {
         info!("Session expired; resetting `pos` and sticky parameters");
 
+        {
+            let lists = self.inner.lists.read().await;
+            for list in lists.values() {
+                // Invalidate in-memory data that would be persisted on disk.
+                list.set_maximum_number_of_rooms(None);
+
+                // Invalidate the sticky data for this list.
+                list.invalidate_sticky_data();
+            }
+        }
+
+        // Remove the cached sliding sync state as well.
         {
             let mut position = self.inner.position.lock().await;
+
+            // Invalidate in memory.
             position.pos = None;
 
+            // Propagate to disk.
+            // Note: this propagates both the sliding sync state and the cached lists'
+            // state to disk.
             if let Err(err) = self.cache_to_storage(&position).await {
-                error!(
-                    "couldn't invalidate sliding sync frozen state when expiring session: {err}"
-                );
+                warn!("Failed to invalidate cached sliding sync state: {err}");
             }
         }
 
@@ -743,8 +758,6 @@ impl SlidingSync {
             // when the session will restart.
             sticky.data_mut().room_subscriptions.clear();
         }
-
-        self.inner.lists.read().await.values().for_each(|list| list.invalidate_sticky_data());
     }
 }