From 3dcea8e6f1da9c5c4fdd03dfc21aad509ae19aba Mon Sep 17 00:00:00 2001
From: Nazar Mokrynskyi <nazar@mokrynskyi.com>
Date: Fri, 19 Jul 2024 22:36:52 +0300
Subject: [PATCH] Clear block gap proactively after DSN sync as well

---
 crates/subspace-service/src/sync_from_dsn.rs | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/crates/subspace-service/src/sync_from_dsn.rs b/crates/subspace-service/src/sync_from_dsn.rs
index 8b3de1f6d7..33d81346da 100644
--- a/crates/subspace-service/src/sync_from_dsn.rs
+++ b/crates/subspace-service/src/sync_from_dsn.rs
@@ -13,6 +13,7 @@ use sc_client_api::{AuxStore, BlockBackend, BlockchainEvents};
 use sc_consensus::import_queue::ImportQueueService;
 use sc_consensus_subspace::archiver::SegmentHeadersStore;
 use sc_network::service::traits::NetworkService;
+use sc_service::ClientExt;
 use sp_api::ProvideRuntimeApi;
 use sp_blockchain::HeaderBackend;
 use sp_consensus_subspace::{FarmerPublicKey, SubspaceApi};
@@ -84,7 +85,7 @@ enum NotificationReason {
 /// Create node observer that will track node state and send notifications to worker to start sync
 /// from DSN.
 #[allow(clippy::too_many_arguments)]
-pub(super) fn create_observer_and_worker<Block, AS, Client, PG>(
+pub(super) fn create_observer_and_worker<Block, Backend, AS, Client, PG>(
     segment_headers_store: SegmentHeadersStore<AS>,
     network_service: Arc<dyn NetworkService>,
     node: Node,
@@ -99,11 +100,13 @@ pub(super) fn create_observer_and_worker<Block, AS, Client, PG>(
 )
 where
     Block: BlockT,
+    Backend: sc_client_api::Backend<Block>,
     AS: AuxStore + Send + Sync + 'static,
     Client: HeaderBackend<Block>
         + BlockBackend<Block>
         + BlockchainEvents<Block>
         + ProvideRuntimeApi<Block>
+        + ClientExt<Block, Backend>
         + Send
         + Sync
         + 'static,
@@ -247,7 +250,7 @@ async fn create_substrate_network_observer(
 }
 
 #[allow(clippy::too_many_arguments)]
-async fn create_worker<Block, AS, IQS, Client, PG>(
+async fn create_worker<Block, Backend, AS, IQS, Client, PG>(
     segment_headers_store: SegmentHeadersStore<AS>,
     node: &Node,
     client: &Client,
@@ -259,10 +262,12 @@ async fn create_worker<Block, AS, IQS, Client, PG>(
 ) -> Result<(), sc_service::Error>
 where
     Block: BlockT,
+    Backend: sc_client_api::Backend<Block>,
     AS: AuxStore + Send + Sync + 'static,
     Client: HeaderBackend<Block>
         + BlockBackend<Block>
         + ProvideRuntimeApi<Block>
+        + ClientExt<Block, Backend>
         + Send
         + Sync
         + 'static,
@@ -329,6 +334,11 @@ where
             }
         }
 
+        // Clear the block gap that arises from first block import with a much higher number than
+        // previously (resulting in a gap)
+        // TODO: This is a hack and better solution is needed: https://github.com/paritytech/polkadot-sdk/issues/4407
+        client.clear_block_gap()?;
+
         debug!("Finished DSN sync");
 
         pause_sync.store(false, Ordering::Release);