automatically retry returning data in syncv3

src/api/client/sync/v3.rs

@@ -124,6 +124,33 @@ pub(crate) async fn sync_events_route(
 	// Setup watchers, so if there's no response, we can wait for them
 	let watcher = services.sync.watch(sender_user, sender_device);
 
+	let response = build_sync_events(services, &body).await?;
+	if body.body.full_state
+		|| !(response.rooms.is_empty()
+			&& response.presence.is_empty()
+			&& response.account_data.is_empty()
+			&& response.device_lists.is_empty()
+			&& response.to_device.is_empty())
+	{
+		return Ok(response);
+	}
+
+	// Hang a few seconds so requests are not spammed
+	// Stop hanging if new info arrives
+	let default = Duration::from_secs(30);
+	let duration = cmp::min(body.body.timeout.unwrap_or(default), default);
+	_ = tokio::time::timeout(duration, watcher).await;
+
+	// Retry returning data
+	build_sync_events(services, &body).await
+}
+
+pub(crate) async fn build_sync_events(
+	services: crate::State,
+	body: &Ruma<sync_events::v3::Request>,
+) -> Result<sync_events::v3::Response, RumaResponse<UiaaResponse>> {
+	let (sender_user, sender_device) = body.sender();
+
 	let next_batch = services.globals.current_count()?;
 	let next_batch_string = next_batch.to_string();
 
@@ -327,21 +354,6 @@ pub(crate) async fn sync_events_route(
 		to_device: ToDevice { events: to_device_events },
 	};
 
-	// TODO: Retry the endpoint instead of returning
-	if !full_state
-		&& response.rooms.is_empty()
-		&& response.presence.is_empty()
-		&& response.account_data.is_empty()
-		&& response.device_lists.is_empty()
-		&& response.to_device.is_empty()
-	{
-		// Hang a few seconds so requests are not spammed
-		// Stop hanging if new info arrives
-		let default = Duration::from_secs(30);
-		let duration = cmp::min(body.body.timeout.unwrap_or(default), default);
-		_ = tokio::time::timeout(duration, watcher).await;
-	}
-
 	Ok(response)
 }