Merge pull request #3540 from Hywan/fix-ui-roomlist-latest-event

chore(ui): `room_list_service::Room::latest_event` no longer uses `SlidingSyncRoom` (+ drop `SlidingSyncRoomExt`)

crates/matrix-sdk-ui/src/room_list_service/room.rs

@@ -22,7 +22,7 @@ use ruma::{api::client::sync::sync_events::v4::RoomSubscription, events::StateEv
 
 use super::Error;
 use crate::{
-    timeline::{EventTimelineItem, SlidingSyncRoomExt, TimelineBuilder},
+    timeline::{EventTimelineItem, TimelineBuilder},
     Timeline,
 };
 
@@ -150,26 +150,38 @@ impl Room {
 
     /// Get the latest event in the timeline.
     ///
-    /// The latest event comes first from the `Timeline` if it exists and if it
-    /// contains a local event. Otherwise, it comes from the cache. This method
-    /// does not fetch any events or calculate anything — if it's not
-    /// already available, we return `None`.
+    /// The latest event comes first from the `Timeline`, it can be a local or a
+    /// remote event. Note that the `Timeline` can have more information esp. if
+    /// it has run a backpagination for example. Otherwise if the `Timeline`
+    /// doesn't have any latest event, it comes from the cache. This method
+    /// does not fetch any events or calculate anything — if it's not already
+    /// available, we return `None`.
+    ///
+    /// Reminder: this method also returns `None` is the latest event is not
+    /// suitable for use in a message preview.
     pub async fn latest_event(&self) -> Option<EventTimelineItem> {
         // Look for a local event in the `Timeline`.
         //
         // First off, let's see if a `Timeline` exists…
         if let Some(timeline) = self.inner.timeline.get() {
             // If it contains a `latest_event`…
             if let Some(timeline_last_event) = timeline.latest_event().await {
-                // If it's a local echo…
-                if timeline_last_event.is_local_echo() {
-                    return Some(timeline_last_event);
-                }
+                // If it's a local event or a remote event, we return it.
+                return Some(timeline_last_event);
             }
         }
 
         // Otherwise, fallback to the classical path.
-        self.inner.sliding_sync_room.latest_timeline_item().await
+        if let Some(latest_event) = self.inner.room.latest_event() {
+            EventTimelineItem::from_latest_event(
+                self.inner.room.client(),
+                self.inner.room.room_id(),
+                latest_event,
+            )
+            .await
+        } else {
+            None
+        }
     }
 
     /// Create a new [`TimelineBuilder`] with the default configuration.

crates/matrix-sdk-ui/src/timeline/mod.rs

@@ -78,7 +78,6 @@ mod pagination;
 mod polls;
 mod reactions;
 mod read_receipts;
-mod sliding_sync_ext;
 #[cfg(test)]
 mod tests;
 #[cfg(feature = "e2e-encryption")]
@@ -102,7 +101,6 @@ pub use self::{
     pagination::LiveBackPaginationStatus,
     polls::PollResult,
     reactions::ReactionSenderData,
-    sliding_sync_ext::SlidingSyncRoomExt,
     traits::RoomExt,
     virtual_item::VirtualTimelineItem,
 };

crates/matrix-sdk/src/sliding_sync/README.md

@@ -343,10 +343,6 @@ copies accordingly. Because of where the loop sits in the stack, that can
 be a bit tedious though, so lists and rooms have an additional way of
 subscribing to updates via [`eyeball`].
 
-The `Timeline` one can receive per room by calling `.timeline()` (from
-`matrix_sdk_ui::timeline::SlidingSyncRoomExt`) will be populated with the
-currently cached timeline events.
-
 ## Caching
 
 All room data, for filled but also _invalidated_ rooms, including the entire