Add a proper error type to ContinuallyRan

This isn't necessary. Because we just log the error, we never match off of it,
we don't need any structure beyond String (or now Debug, which still gives us
a way to print the error). This is for the ergonomics of not having to
constantly write `.map_err(|e| format!("{e:?}"))`.

coordinator/p2p/libp2p/src/dial.rs

@@ -5,7 +5,7 @@ use rand_core::{RngCore, OsRng};
 
 use tokio::sync::mpsc;
 
-use serai_client::Serai;
+use serai_client::{SeraiError, Serai};
 
 use libp2p::{
   core::multiaddr::{Protocol, Multiaddr},
@@ -50,7 +50,9 @@ impl ContinuallyRan for DialTask {
   const DELAY_BETWEEN_ITERATIONS: u64 = 5 * 60;
   const MAX_DELAY_BETWEEN_ITERATIONS: u64 = 10 * 60;
 
-  fn run_iteration(&mut self) -> impl Send + Future<Output = Result<bool, String>> {
+  type Error = SeraiError;
+
+  fn run_iteration(&mut self) -> impl Send + Future<Output = Result<bool, Self::Error>> {
     async move {
       self.validators.update().await?;
 
@@ -83,8 +85,7 @@ impl ContinuallyRan for DialTask {
               .unwrap_or(0)
               .saturating_sub(1))
         {
-          let mut potential_peers =
-            self.serai.p2p_validators(network).await.map_err(|e| format!("{e:?}"))?;
+          let mut potential_peers = self.serai.p2p_validators(network).await?;
           for _ in 0 .. (TARGET_PEERS_PER_NETWORK - peer_count) {
             if potential_peers.is_empty() {
               break;

coordinator/p2p/libp2p/src/validators.rs

@@ -4,7 +4,7 @@ use std::{
   collections::{HashSet, HashMap},
 };
 
-use serai_client::{primitives::NetworkId, validator_sets::primitives::Session, Serai};
+use serai_client::{primitives::NetworkId, validator_sets::primitives::Session, SeraiError, Serai};
 
 use serai_task::{Task, ContinuallyRan};
 
@@ -50,9 +50,8 @@ impl Validators {
   async fn session_changes(
     serai: impl Borrow<Serai>,
     sessions: impl Borrow<HashMap<NetworkId, Session>>,
-  ) -> Result<Vec<(NetworkId, Session, HashSet<PeerId>)>, String> {
-    let temporal_serai =
-      serai.borrow().as_of_latest_finalized_block().await.map_err(|e| format!("{e:?}"))?;
+  ) -> Result<Vec<(NetworkId, Session, HashSet<PeerId>)>, SeraiError> {
+    let temporal_serai = serai.borrow().as_of_latest_finalized_block().await?;
     let temporal_serai = temporal_serai.validator_sets();
 
     let mut session_changes = vec![];
@@ -69,7 +68,7 @@ impl Validators {
           let session = match temporal_serai.session(network).await {
             Ok(Some(session)) => session,
             Ok(None) => return Ok(None),
-            Err(e) => return Err(format!("{e:?}")),
+            Err(e) => return Err(e),
           };
 
           if sessions.get(&network) == Some(&session) {
@@ -81,7 +80,7 @@ impl Validators {
                 session,
                 validators.into_iter().map(peer_id_from_public).collect(),
               ))),
-              Err(e) => Err(format!("{e:?}")),
+              Err(e) => Err(e),
             }
           }
         });
@@ -147,7 +146,7 @@ impl Validators {
   }
 
   /// Update the view of the validators.
-  pub(crate) async fn update(&mut self) -> Result<(), String> {
+  pub(crate) async fn update(&mut self) -> Result<(), SeraiError> {
     let session_changes = Self::session_changes(&*self.serai, &self.sessions).await?;
     self.incorporate_session_changes(session_changes);
     Ok(())
@@ -200,13 +199,13 @@ impl ContinuallyRan for UpdateValidatorsTask {
   const DELAY_BETWEEN_ITERATIONS: u64 = 60;
   const MAX_DELAY_BETWEEN_ITERATIONS: u64 = 5 * 60;
 
-  fn run_iteration(&mut self) -> impl Send + Future<Output = Result<bool, String>> {
+  type Error = SeraiError;
+
+  fn run_iteration(&mut self) -> impl Send + Future<Output = Result<bool, Self::Error>> {
     async move {
       let session_changes = {
         let validators = self.validators.read().await;
-        Validators::session_changes(validators.serai.clone(), validators.sessions.clone())
-          .await
-          .map_err(|e| format!("{e:?}"))?
+        Validators::session_changes(validators.serai.clone(), validators.sessions.clone()).await?
       };
       self.validators.write().await.incorporate_session_changes(session_changes);
       Ok(true)

coordinator/p2p/src/heartbeat.rs

@@ -45,7 +45,9 @@ pub(crate) struct HeartbeatTask<TD: Db, Tx: TransactionTrait, P: P2p> {
 }
 
 impl<TD: Db, Tx: TransactionTrait, P: P2p> ContinuallyRan for HeartbeatTask<TD, Tx, P> {
-  fn run_iteration(&mut self) -> impl Send + Future<Output = Result<bool, String>> {
+  type Error = String;
+
+  fn run_iteration(&mut self) -> impl Send + Future<Output = Result<bool, Self::Error>> {
     async move {
       // If our blockchain hasn't had a block in the past minute, trigger the heartbeat protocol
       const TIME_TO_TRIGGER_SYNCING: Duration = Duration::from_secs(60);