Fix inconsistent latest_block_hash (#1424)

* Add `best_hash` method

* Update earliest tag matched value

* Fix CI tests

* Code clean

* Fix review comments

* Update comment

* Fix compile after solving conflicts

* Remove the broken changes

* Update trait bound

* Simplify trait bound

client/api/src/backend.rs

@@ -52,6 +52,9 @@ pub trait Backend<Block: BlockT>: Send + Sync {
 	fn is_indexed(&self) -> bool {
 		self.log_indexer().is_indexed()
 	}
+
+	/// Get the hash of the latest substrate block fully indexed by the backend.
+	async fn latest_block_hash(&self) -> Result<Block::Hash, String>;
 }
 
 #[derive(Debug, Eq, PartialEq)]

client/cli/src/frontier_db_cmd/mapping_db.rs

@@ -40,22 +40,21 @@ pub enum MappingKey {
 	EthBlockOrTransactionHash(H256),
 }
 
-pub struct MappingDb<'a, C, B: BlockT> {
+pub struct MappingDb<'a, B: BlockT, C> {
 	cmd: &'a FrontierDbCmd,
 	client: Arc<C>,
-	backend: Arc<fc_db::kv::Backend<B>>,
+	backend: Arc<fc_db::kv::Backend<B, C>>,
 }
 
-impl<'a, C, B: BlockT> MappingDb<'a, C, B>
+impl<'a, B: BlockT, C> MappingDb<'a, B, C>
 where
-	C: ProvideRuntimeApi<B>,
+	C: HeaderBackend<B> + ProvideRuntimeApi<B>,
 	C::Api: EthereumRuntimeRPCApi<B>,
-	C: HeaderBackend<B>,
 {
 	pub fn new(
 		cmd: &'a FrontierDbCmd,
 		client: Arc<C>,
-		backend: Arc<fc_db::kv::Backend<B>>,
+		backend: Arc<fc_db::kv::Backend<B, C>>,
 	) -> Self {
 		Self {
 			cmd,
@@ -176,4 +175,4 @@ where
 	}
 }
 
-impl<'a, C, B: BlockT> FrontierDbMessage for MappingDb<'a, C, B> {}
+impl<'a, B: BlockT, C: HeaderBackend<B>> FrontierDbMessage for MappingDb<'a, B, C> {}

client/cli/src/frontier_db_cmd/meta_db.rs

@@ -24,6 +24,7 @@ use std::{
 
 use ethereum_types::H256;
 use serde::Deserialize;
+use sp_blockchain::HeaderBackend;
 // Substrate
 use sp_runtime::traits::Block as BlockT;
 
@@ -57,13 +58,13 @@ impl FromStr for MetaKey {
 	}
 }
 
-pub struct MetaDb<'a, B: BlockT> {
+pub struct MetaDb<'a, B: BlockT, C> {
 	cmd: &'a FrontierDbCmd,
-	backend: Arc<fc_db::kv::Backend<B>>,
+	backend: Arc<fc_db::kv::Backend<B, C>>,
 }
 
-impl<'a, B: BlockT> MetaDb<'a, B> {
-	pub fn new(cmd: &'a FrontierDbCmd, backend: Arc<fc_db::kv::Backend<B>>) -> Self {
+impl<'a, B: BlockT, C: HeaderBackend<B>> MetaDb<'a, B, C> {
+	pub fn new(cmd: &'a FrontierDbCmd, backend: Arc<fc_db::kv::Backend<B, C>>) -> Self {
 		Self { cmd, backend }
 	}
 
@@ -151,4 +152,4 @@ impl<'a, B: BlockT> MetaDb<'a, B> {
 	}
 }
 
-impl<'a, B: BlockT> FrontierDbMessage for MetaDb<'a, B> {}
+impl<'a, B: BlockT, C: HeaderBackend<B>> FrontierDbMessage for MetaDb<'a, B, C> {}

client/cli/src/frontier_db_cmd/mod.rs

@@ -98,15 +98,14 @@ pub enum DbValue<H> {
 }
 
 impl FrontierDbCmd {
-	pub fn run<C, B: BlockT>(
+	pub fn run<B: BlockT, C>(
 		&self,
 		client: Arc<C>,
-		backend: Arc<fc_db::kv::Backend<B>>,
+		backend: Arc<fc_db::kv::Backend<B, C>>,
 	) -> sc_cli::Result<()>
 	where
-		C: ProvideRuntimeApi<B>,
+		C: HeaderBackend<B> + ProvideRuntimeApi<B>,
 		C::Api: fp_rpc::EthereumRuntimeRPCApi<B>,
-		C: HeaderBackend<B>,
 	{
 		match self.column {
 			Column::Meta => {

client/cli/src/frontier_db_cmd/tests.rs

@@ -49,8 +49,8 @@ type OpaqueBlock =
 pub fn open_frontier_backend<Block: BlockT, C: HeaderBackend<Block>>(
 	client: Arc<C>,
 	path: PathBuf,
-) -> Result<Arc<fc_db::kv::Backend<Block>>, String> {
-	Ok(Arc::new(fc_db::kv::Backend::<Block>::new(
+) -> Result<Arc<fc_db::kv::Backend<Block, C>>, String> {
+	Ok(Arc::new(fc_db::kv::Backend::<Block, C>::new(
 		client,
 		&fc_db::kv::DatabaseSettings {
 			source: sc_client_db::DatabaseSource::RocksDb {

client/db/src/kv/mod.rs

@@ -62,14 +62,15 @@ pub mod static_keys {
 }
 
 #[derive(Clone)]
-pub struct Backend<Block: BlockT> {
+pub struct Backend<Block: BlockT, C> {
+	client: Arc<C>,
 	meta: Arc<MetaDb<Block>>,
 	mapping: Arc<MappingDb<Block>>,
 	log_indexer: LogIndexerBackend<Block>,
 }
 
 #[async_trait::async_trait]
-impl<Block: BlockT> fc_api::Backend<Block> for Backend<Block> {
+impl<Block: BlockT, C: HeaderBackend<Block>> fc_api::Backend<Block> for Backend<Block, C> {
 	async fn block_hash(
 		&self,
 		ethereum_block_hash: &H256,
@@ -88,6 +89,10 @@ impl<Block: BlockT> fc_api::Backend<Block> for Backend<Block> {
 	fn log_indexer(&self) -> &dyn fc_api::LogIndexerBackend<Block> {
 		&self.log_indexer
 	}
+
+	async fn latest_block_hash(&self) -> Result<Block::Hash, String> {
+		Ok(self.client.info().best_hash)
+	}
 }
 
 #[derive(Clone, Default)]
@@ -115,8 +120,8 @@ pub fn frontier_database_dir(db_config_dir: &Path, db_path: &str) -> PathBuf {
 	db_config_dir.join("frontier").join(db_path)
 }
 
-impl<Block: BlockT> Backend<Block> {
-	pub fn open<C: HeaderBackend<Block>>(
+impl<Block: BlockT, C: HeaderBackend<Block>> Backend<Block, C> {
+	pub fn open(
 		client: Arc<C>,
 		database: &DatabaseSource,
 		db_config_dir: &Path,
@@ -148,13 +153,11 @@ impl<Block: BlockT> Backend<Block> {
 		)
 	}
 
-	pub fn new<C: HeaderBackend<Block>>(
-		client: Arc<C>,
-		config: &DatabaseSettings,
-	) -> Result<Self, String> {
-		let db = utils::open_database::<Block, C>(client, config)?;
+	pub fn new(client: Arc<C>, config: &DatabaseSettings) -> Result<Self, String> {
+		let db = utils::open_database::<Block, C>(client.clone(), config)?;
 
 		Ok(Self {
+			client,
 			mapping: Arc::new(MappingDb {
 				db: db.clone(),
 				write_lock: Arc::new(Mutex::new(())),

client/db/src/kv/upgrade.rs

@@ -348,8 +348,10 @@ mod tests {
 	pub fn open_frontier_backend<Block: BlockT, C: HeaderBackend<Block>>(
 		client: Arc<C>,
 		setting: &crate::kv::DatabaseSettings,
-	) -> Result<Arc<crate::kv::Backend<Block>>, String> {
-		Ok(Arc::new(crate::kv::Backend::<Block>::new(client, setting)?))
+	) -> Result<Arc<crate::kv::Backend<Block, C>>, String> {
+		Ok(Arc::new(crate::kv::Backend::<Block, C>::new(
+			client, setting,
+		)?))
 	}
 
 	#[cfg_attr(not(feature = "rocksdb"), ignore)]

client/db/src/lib.rs

@@ -18,6 +18,8 @@
 
 #![warn(unused_crate_dependencies)]
 
+use std::sync::Arc;
+
 // Substrate
 pub use sc_client_db::DatabaseSource;
 use sp_runtime::traits::Block as BlockT;
@@ -27,8 +29,8 @@ pub mod kv;
 pub mod sql;
 
 #[derive(Clone)]
-pub enum Backend<Block: BlockT> {
-	KeyValue(kv::Backend<Block>),
+pub enum Backend<Block: BlockT, C> {
+	KeyValue(Arc<kv::Backend<Block, C>>),
 	#[cfg(feature = "sql")]
-	Sql(sql::Backend<Block>),
+	Sql(Arc<sql::Backend<Block>>),
 }

client/db/src/sql/mod.rs

@@ -96,7 +96,6 @@ pub enum BackendConfig<'a> {
 pub struct Backend<Block: BlockT> {
 	/// The Sqlite connection.
 	pool: SqlitePool,
-
 	/// The additional overrides for the logs handler.
 	storage_override: Arc<dyn StorageOverride<Block>>,
 
@@ -656,7 +655,7 @@ where
 	}
 
 	/// Retrieve the block hash for the last indexed canon block.
-	pub async fn get_last_indexed_canon_block(&self) -> Result<H256, Error> {
+	pub async fn last_indexed_canon_block(&self) -> Result<H256, Error> {
 		let row = sqlx::query(
 			"SELECT b.substrate_block_hash FROM blocks AS b
 			INNER JOIN sync_status AS s
@@ -823,6 +822,15 @@ impl<Block: BlockT<Hash = H256>> fc_api::Backend<Block> for Backend<Block> {
 	fn log_indexer(&self) -> &dyn fc_api::LogIndexerBackend<Block> {
 		self
 	}
+
+	async fn latest_block_hash(&self) -> Result<Block::Hash, String> {
+		// Retrieves the block hash for the latest indexed block, maybe it's not canon.
+		sqlx::query("SELECT substrate_block_hash FROM blocks ORDER BY block_number DESC LIMIT 1")
+			.fetch_one(self.pool())
+			.await
+			.map(|row| H256::from_slice(&row.get::<Vec<u8>, _>(0)[..]))
+			.map_err(|e| format!("Failed to fetch best hash: {}", e))
+	}
 }
 
 #[async_trait::async_trait]

client/mapping-sync/src/kv/mod.rs

@@ -37,9 +37,9 @@ use fp_rpc::EthereumRuntimeRPCApi;
 
 use crate::{EthereumBlockNotification, EthereumBlockNotificationSinks, SyncStrategy};
 
-pub fn sync_block<Block: BlockT>(
+pub fn sync_block<Block: BlockT, C: HeaderBackend<Block>>(
 	storage_override: Arc<dyn StorageOverride<Block>>,
-	backend: &fc_db::kv::Backend<Block>,
+	backend: &fc_db::kv::Backend<Block, C>,
 	header: &Block::Header,
 ) -> Result<(), String> {
 	let substrate_block_hash = header.hash();
@@ -100,11 +100,11 @@ pub fn sync_block<Block: BlockT>(
 
 pub fn sync_genesis_block<Block: BlockT, C>(
 	client: &C,
-	backend: &fc_db::kv::Backend<Block>,
+	backend: &fc_db::kv::Backend<Block, C>,
 	header: &Block::Header,
 ) -> Result<(), String>
 where
-	C: ProvideRuntimeApi<Block>,
+	C: HeaderBackend<Block> + ProvideRuntimeApi<Block>,
 	C::Api: EthereumRuntimeRPCApi<Block>,
 {
 	let substrate_block_hash = header.hash();
@@ -148,7 +148,7 @@ pub fn sync_one_block<Block: BlockT, C, BE>(
 	client: &C,
 	substrate_backend: &BE,
 	storage_override: Arc<dyn StorageOverride<Block>>,
-	frontier_backend: &fc_db::kv::Backend<Block>,
+	frontier_backend: &fc_db::kv::Backend<Block, C>,
 	sync_from: <Block::Header as HeaderT>::Number,
 	strategy: SyncStrategy,
 	sync_oracle: Arc<dyn SyncOracle + Send + Sync + 'static>,
@@ -237,7 +237,7 @@ pub fn sync_blocks<Block: BlockT, C, BE>(
 	client: &C,
 	substrate_backend: &BE,
 	storage_override: Arc<dyn StorageOverride<Block>>,
-	frontier_backend: &fc_db::kv::Backend<Block>,
+	frontier_backend: &fc_db::kv::Backend<Block, C>,
 	limit: usize,
 	sync_from: <Block::Header as HeaderT>::Number,
 	strategy: SyncStrategy,
@@ -271,13 +271,14 @@ where
 	Ok(synced_any)
 }
 
-pub fn fetch_header<Block: BlockT, BE>(
+pub fn fetch_header<Block: BlockT, C, BE>(
 	substrate_backend: &BE,
-	frontier_backend: &fc_db::kv::Backend<Block>,
+	frontier_backend: &fc_db::kv::Backend<Block, C>,
 	checking_tip: Block::Hash,
 	sync_from: <Block::Header as HeaderT>::Number,
 ) -> Result<Option<Block::Header>, String>
 where
+	C: HeaderBackend<Block>,
 	BE: HeaderBackend<Block>,
 {
 	if frontier_backend.mapping().is_synced(&checking_tip)? {

client/mapping-sync/src/kv/worker.rs

@@ -47,7 +47,7 @@ pub struct MappingSyncWorker<Block: BlockT, C, BE> {
 	client: Arc<C>,
 	substrate_backend: Arc<BE>,
 	storage_override: Arc<dyn StorageOverride<Block>>,
-	frontier_backend: Arc<fc_db::kv::Backend<Block>>,
+	frontier_backend: Arc<fc_db::kv::Backend<Block, C>>,
 
 	have_next: bool,
 	retry_times: usize,
@@ -68,7 +68,7 @@ impl<Block: BlockT, C, BE> MappingSyncWorker<Block, C, BE> {
 		client: Arc<C>,
 		substrate_backend: Arc<BE>,
 		storage_override: Arc<dyn StorageOverride<Block>>,
-		frontier_backend: Arc<fc_db::kv::Backend<Block>>,
+		frontier_backend: Arc<fc_db::kv::Backend<Block, C>>,
 		retry_times: usize,
 		sync_from: <Block::Header as HeaderT>::Number,
 		strategy: SyncStrategy,
@@ -250,7 +250,7 @@ mod tests {
 		let storage_override = Arc::new(SchemaV3StorageOverride::new(client.clone()));
 
 		let frontier_backend = Arc::new(
-			fc_db::kv::Backend::<OpaqueBlock>::new(
+			fc_db::kv::Backend::<OpaqueBlock, _>::new(
 				client.clone(),
 				&fc_db::kv::DatabaseSettings {
 					source: sc_client_db::DatabaseSource::RocksDb {
@@ -392,7 +392,7 @@ mod tests {
 		let storage_override = Arc::new(SchemaV3StorageOverride::new(client.clone()));
 
 		let frontier_backend = Arc::new(
-			fc_db::kv::Backend::<OpaqueBlock>::new(
+			fc_db::kv::Backend::<OpaqueBlock, _>::new(
 				client.clone(),
 				&fc_db::kv::DatabaseSettings {
 					source: sc_client_db::DatabaseSource::RocksDb {

client/mapping-sync/src/sql/mod.rs

@@ -89,7 +89,7 @@ where
 				match cmd {
 					WorkerCommand::ResumeSync => {
 						// Attempt to resume from last indexed block. If there is no data in the db, sync genesis.
-						match indexer_backend.get_last_indexed_canon_block().await.ok() {
+						match indexer_backend.last_indexed_canon_block().await.ok() {
 							Some(last_block_hash) => {
 								log::debug!(target: "frontier-sql", "Resume from last block {last_block_hash:?}");
 								if let Some(parent_hash) = client

client/rpc/src/lib.rs

@@ -205,7 +205,13 @@ pub mod frontier_backend_client {
 				}
 			}
 			BlockNumberOrHash::Num(number) => Some(BlockId::Number(number.unique_saturated_into())),
-			BlockNumberOrHash::Latest => Some(BlockId::Hash(client.info().best_hash)),
+			BlockNumberOrHash::Latest => match backend.latest_block_hash().await {
+				Ok(hash) => Some(BlockId::Hash(hash)),
+				Err(e) => {
+					log::warn!(target: "rpc", "Failed to get latest block hash from the sql db: {:?}", e);
+					Some(BlockId::Hash(client.info().best_hash))
+				}
+			},
 			BlockNumberOrHash::Earliest => Some(BlockId::Hash(client.info().genesis_hash)),
 			BlockNumberOrHash::Pending => None,
 			BlockNumberOrHash::Safe => Some(BlockId::Hash(client.info().finalized_hash)),
@@ -363,8 +369,8 @@ mod tests {
 	fn open_frontier_backend<Block: BlockT, C: HeaderBackend<Block>>(
 		client: Arc<C>,
 		path: PathBuf,
-	) -> Result<Arc<fc_db::kv::Backend<Block>>, String> {
-		Ok(Arc::new(fc_db::kv::Backend::<Block>::new(
+	) -> Result<Arc<fc_db::kv::Backend<Block, C>>, String> {
+		Ok(Arc::new(fc_db::kv::Backend::<Block, C>::new(
 			client,
 			&fc_db::kv::DatabaseSettings {
 				source: sc_client_db::DatabaseSource::RocksDb {

template/node/src/command.rs

@@ -219,7 +219,7 @@ pub fn run() -> sc_cli::Result<()> {
 				let (client, _, _, _, frontier_backend) =
 					service::new_chain_ops(&mut config, &cli.eth)?;
 				let frontier_backend = match frontier_backend {
-					fc_db::Backend::KeyValue(kv) => std::sync::Arc::new(kv),
+					fc_db::Backend::KeyValue(kv) => kv,
 					_ => panic!("Only fc_db::Backend::KeyValue supported"),
 				};
 				cmd.run(client, frontier_backend)