Gossip recently computed light client data (#7023)

michaelsproul · michaelsproul · commit 96d0db908fcf · 2025-06-23T17:30:33.000+10:00
Squashed commit of the following: commit 7b861ac Author: Eitan Seri-Levi <eserilev@ucsc.edu> Date: Sun Jun 22 17:14:32 2025 +0300 / commit 8ca4ec1 Merge: 08510b9 d509246 Author: Eitan Seri-Levi <eserilev@ucsc.edu> Date: Sun Jun 22 16:51:15 2025 +0300 Merge branch 'unstable' of https://github.com/sigp/lighthouse into gossip-light-client-updates commit 08510b9 Merge: e7614a2 54f7bc5 Author: Eitan Seri-Levi <eserilev@ucsc.edu> Date: Mon Apr 21 16:36:20 2025 -0700 Merge branch 'release-v7.0.0' into gossip-light-client-updates commit e7614a2 Merge: a2b2eb3 c7acffc Author: Eitan Seri-Levi <eserilev@ucsc.edu> Date: Sun Apr 20 10:19:47 2025 -0700 Merge branch 'release-v7.0.0' into gossip-light-client-updates commit a2b2eb3 Merge: d223840 8ce9edc Author: Eitan Seri-Levi <eserilev@ucsc.edu> Date: Mon Mar 17 09:25:32 2025 -0600 Merge branch 'release-v7.0.0' into gossip-light-client-updates commit d223840 Merge: 75f00af 522b3cb Author: Eitan Seri-Levi <eserilev@ucsc.edu> Date: Sun Feb 23 21:17:25 2025 -0800 Merge branch 'release-v7.0.0' of https://github.com/sigp/lighthouse into gossip-light-client-updates commit 75f00af Author: Eitan Seri-Levi <eserilev@ucsc.edu> Date: Sun Feb 23 21:04:07 2025 -0800 fix commit b51196e Author: Eitan Seri-Levi <eserilev@ucsc.edu> Date: Sun Feb 23 16:41:27 2025 -0800 fix comments commit f99fef7 Author: Eitan Seri-Levi <eserilev@ucsc.edu> Date: Sun Feb 23 16:39:08 2025 -0800 gossip light client data durnig sync committee contributions commit 29b5614 Author: Eitan Seri-Levi <eserilev@ucsc.edu> Date: Fri Feb 21 06:53:54 2025 -0800 add logic to gossip light client updates post computation
diff --git a/beacon_node/beacon_chain/src/light_client_server_cache.rs b/beacon_node/beacon_chain/src/light_client_server_cache.rs
@@ -40,6 +40,10 @@ pub struct LightClientServerCache<T: BeaconChainTypes> {
     latest_written_current_sync_committee: RwLock<Option<Arc<SyncCommittee<T::EthSpec>>>>,
     /// Caches state proofs by block root
     prev_block_cache: Mutex<lru::LruCache<Hash256, LightClientCachedData<T::EthSpec>>>,
+    /// Tracks the latest broadcasted finality update
+    latest_broadcasted_finality_update: RwLock<Option<LightClientFinalityUpdate<T::EthSpec>>>,
+    /// Tracks the latest broadcasted optimistic update
+    latest_broadcasted_optimistic_update: RwLock<Option<LightClientOptimisticUpdate<T::EthSpec>>>,
 }
 
 impl<T: BeaconChainTypes> LightClientServerCache<T> {
@@ -49,6 +53,8 @@ impl<T: BeaconChainTypes> LightClientServerCache<T> {
             latest_optimistic_update: None.into(),
             latest_light_client_update: None.into(),
             latest_written_current_sync_committee: None.into(),
+            latest_broadcasted_finality_update: None.into(),
+            latest_broadcasted_optimistic_update: None.into(),
             prev_block_cache: lru::LruCache::new(PREV_BLOCK_CACHE_SIZE).into(),
         }
     }
@@ -334,10 +340,65 @@ impl<T: BeaconChainTypes> LightClientServerCache<T> {
         Ok(new_value)
     }
 
+    /// Checks if we've already broadcasted the latest finality update.
+    /// If we haven't, update the `latest_broadcasted_finality_update` cache
+    /// and return the latest finality update for broadcasting, else return `None`.
+    pub fn should_broadcast_latest_finality_update(
+        &self,
+    ) -> Option<LightClientFinalityUpdate<T::EthSpec>> {
+        if let Some(latest_finality_update) = self.get_latest_finality_update() {
+            let latest_broadcasted_finality_update =
+                self.latest_broadcasted_finality_update.read().clone();
+            match latest_broadcasted_finality_update {
+                Some(latest_broadcasted_finality_update) => {
+                    if latest_broadcasted_finality_update != latest_finality_update {
+                        *self.latest_broadcasted_finality_update.write() =
+                            Some(latest_finality_update.clone());
+                        return Some(latest_finality_update);
+                    }
+                }
+                None => {
+                    *self.latest_broadcasted_finality_update.write() =
+                        Some(latest_finality_update.clone());
+                    return Some(latest_finality_update);
+                }
+            }
+        }
+
+        None
+    }
+
     pub fn get_latest_finality_update(&self) -> Option<LightClientFinalityUpdate<T::EthSpec>> {
         self.latest_finality_update.read().clone()
     }
 
+    /// Checks if we've already broadcasted the latest optimistic update.
+    /// If we haven't, update the `latest_broadcasted_optimistic_update` cache
+    /// and return the latest optimistic update for broadcasting, else return `None`.
+    pub fn should_broadcast_latest_optimistic_update(
+        &self,
+    ) -> Option<LightClientOptimisticUpdate<T::EthSpec>> {
+        if let Some(latest_optimistic_update) = self.get_latest_optimistic_update() {
+            let latest_broadcasted_optimistic_update = self.latest_optimistic_update.read().clone();
+            match latest_broadcasted_optimistic_update {
+                Some(latest_broadcasted_optimistic_update) => {
+                    if latest_broadcasted_optimistic_update != latest_optimistic_update {
+                        *self.latest_broadcasted_optimistic_update.write() =
+                            Some(latest_optimistic_update.clone());
+                        return Some(latest_optimistic_update);
+                    }
+                }
+                None => {
+                    *self.latest_broadcasted_optimistic_update.write() =
+                        Some(latest_optimistic_update.clone());
+                    return Some(latest_optimistic_update);
+                }
+            }
+        }
+
+        None
+    }
+
     pub fn get_latest_optimistic_update(&self) -> Option<LightClientOptimisticUpdate<T::EthSpec>> {
         self.latest_optimistic_update.read().clone()
     }
diff --git a/beacon_node/http_api/src/sync_committees.rs b/beacon_node/http_api/src/sync_committees.rs
@@ -320,6 +320,38 @@ pub fn process_signed_contribution_and_proofs<T: BeaconChainTypes>(
 
     let seen_timestamp = timestamp_now();
 
+    if let Some(latest_optimistic_update) = chain
+        .light_client_server_cache
+        .should_broadcast_latest_optimistic_update()
+    {
+        let _ = publish_pubsub_message(
+            &network_tx,
+            PubsubMessage::LightClientOptimisticUpdate(Box::new(latest_optimistic_update)),
+        )
+        .inspect_err(|e| {
+            error!(
+                error = ?e,
+                "Unable to broadcast latest light client optimistic update"
+            );
+        });
+    };
+
+    if let Some(latest_finality_update) = chain
+        .light_client_server_cache
+        .should_broadcast_latest_finality_update()
+    {
+        let _ = publish_pubsub_message(
+            &network_tx,
+            PubsubMessage::LightClientFinalityUpdate(Box::new(latest_finality_update)),
+        )
+        .inspect_err(|e| {
+            error!(
+                error = ?e,
+                "Unable to broadcast latest light client finality update"
+            );
+        });
+    };
+
     // Verify contributions & broadcast to the network.
     for (index, contribution) in signed_contribution_and_proofs.into_iter().enumerate() {
         let aggregator_index = contribution.message.aggregator_index;
diff --git a/beacon_node/store/src/hot_cold_store.rs b/beacon_node/store/src/hot_cold_store.rs
@@ -3538,7 +3538,7 @@ pub fn get_ancestor_state_root<'a, E: EthSpec, Hot: ItemStore<E>, Cold: ItemStor
             .get_cold_state_root(target_slot)
             .map_err(Box::new)
             .map_err(StateSummaryIteratorError::LoadStateRootError)?
-            .ok_or_else(|| StateSummaryIteratorError::MissingStateRoot {
+            .ok_or(StateSummaryIteratorError::MissingStateRoot {
                 target_slot,
                 state_upper_limit,
             });
