From aeffb05581a9f1e21d3a88f22799279a85a7bea6 Mon Sep 17 00:00:00 2001
From: Thomas Niederberger <thomas@niederb.ch>
Date: Thu, 27 Jul 2023 13:28:36 +0200
Subject: [PATCH] Error handling and documentation

---
 examples/examples/runtime_update_sync.rs |  2 +-
 src/api/rpc_api/runtime_update.rs        | 26 ++++++++++++++++--------
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/examples/examples/runtime_update_sync.rs b/examples/examples/runtime_update_sync.rs
index cd7f80718..d195cf79d 100644
--- a/examples/examples/runtime_update_sync.rs
+++ b/examples/examples/runtime_update_sync.rs
@@ -45,7 +45,7 @@ async fn main() {
 	println!("Current spec_version: {}", api.spec_version());
 
 	let handler = thread::spawn(move || {
-		let runtime_update_detected = update_detector.detect_runtime_update();
+		let runtime_update_detected = update_detector.detect_runtime_update().unwrap();
 		println!("Detected runtime update: {runtime_update_detected}");
 	});
 
diff --git a/src/api/rpc_api/runtime_update.rs b/src/api/rpc_api/runtime_update.rs
index f9a1d8276..355725d79 100644
--- a/src/api/rpc_api/runtime_update.rs
+++ b/src/api/rpc_api/runtime_update.rs
@@ -10,10 +10,13 @@
 	See the License for the specific language governing permissions and
 	limitations under the License.
 */
-use crate::{ac_primitives::Config, rpc::Subscribe, rpc_api::EventSubscriptionFor};
+use crate::{
+	ac_primitives::Config, api::Error, rpc::Subscribe, rpc_api::EventSubscriptionFor, Result,
+};
 use alloc::sync::Arc;
 use core::sync::atomic::{AtomicBool, Ordering};
 
+/// Struct to support waiting for runtime updates
 pub struct RuntimeUpdateDetector<T, Client>
 where
 	T: Config,
@@ -32,6 +35,8 @@ where
 		Self { subscription, external_cancellation: None }
 	}
 
+	/// Provide the `RuntimeUpdateDetector` with the additional option to cancel the waiting
+	/// from the outside
 	pub fn new_with_cancellation(
 		subscription: EventSubscriptionFor<Client, T::Hash>,
 		cancellation: Arc<AtomicBool>,
@@ -39,24 +44,29 @@ where
 		Self { subscription, external_cancellation: Some(cancellation) }
 	}
 
-	/// Returns true if a runtime update was detected, false if the wait was cancelled for some other reason
+	/// Returns true if a runtime update was detected, false if the wait was cancelled
+	/// In principle this method only returns/resolves once a runtime update is detected
 	#[maybe_async::maybe_async(?Send)]
-	pub async fn detect_runtime_update(&mut self) -> bool {
+	pub async fn detect_runtime_update(&mut self) -> Result<bool> {
 		'outer: loop {
 			if let Some(canceled) = &self.external_cancellation {
 				if canceled.load(Ordering::SeqCst) {
-					return false
+					return Ok(false)
 				}
 			}
-			let event_records =
-				self.subscription.next_events_from_metadata().await.unwrap().unwrap();
+			let event_records = self
+				.subscription
+				.next_events_from_metadata()
+				.await
+				.ok_or(Error::Other("Error receiving events".into()))?;
+			let event_records = event_records?;
 			let event_iter = event_records.iter();
 			for event in event_iter {
-				if event.unwrap().is_code_update() {
+				if event?.is_code_update() {
 					break 'outer
 				}
 			}
 		}
-		true
+		Ok(true)
 	}
 }