populate parent hash for indexers

client/rpc/src/eth/block.rs

@@ -68,19 +68,29 @@ where
 			.current_transaction_statuses(schema, substrate_hash)
 			.await;
 
-		let base_fee = client
-			.runtime_api()
-			.gas_price(substrate_hash)
-			.unwrap_or_default();
+		let base_fee = client.runtime_api().gas_price(substrate_hash).ok();
 
 		match (block, statuses) {
-			(Some(block), Some(statuses)) => Ok(Some(rich_block_build(
-				block,
-				statuses.into_iter().map(Some).collect(),
-				Some(hash),
-				full,
-				Some(base_fee),
-			))),
+			(Some(block), Some(statuses)) => {
+				let mut rich_block = rich_block_build(
+					block,
+					statuses.into_iter().map(Option::Some).collect(),
+					Some(hash),
+					full,
+					base_fee,
+				);
+
+				let substrate_hash = H256::from_slice(substrate_hash.as_ref());
+				if let Some(parent_hash) = self
+					.forced_parent_hashes
+					.as_ref()
+					.and_then(|parent_hashes| parent_hashes.get(&substrate_hash).cloned())
+				{
+					rich_block.inner.header.parent_hash = parent_hash
+				}
+
+				Ok(Some(rich_block))
+			}
 			_ => Ok(None),
 		}
 	}
@@ -113,22 +123,30 @@ where
 			.current_transaction_statuses(schema, substrate_hash)
 			.await;
 
-		let base_fee = client
-			.runtime_api()
-			.gas_price(substrate_hash)
-			.unwrap_or_default();
+		let base_fee = client.runtime_api().gas_price(substrate_hash).ok();
 
 		match (block, statuses) {
 			(Some(block), Some(statuses)) => {
 				let hash = H256::from(keccak_256(&rlp::encode(&block.header)));
 
-				Ok(Some(rich_block_build(
+				let mut rich_block = rich_block_build(
 					block,
 					statuses.into_iter().map(Option::Some).collect(),
 					Some(hash),
 					full,
-					Some(base_fee),
-				)))
+					base_fee,
+				);
+
+				let substrate_hash = H256::from_slice(substrate_hash.as_ref());
+				if let Some(parent_hash) = self
+					.forced_parent_hashes
+					.as_ref()
+					.and_then(|parent_hashes| parent_hashes.get(&substrate_hash).cloned())
+				{
+					rich_block.inner.header.parent_hash = parent_hash
+				}
+
+				Ok(Some(rich_block))
 			}
 			_ => Ok(None),
 		}

client/rpc/src/eth/mod.rs

@@ -88,6 +88,7 @@ pub struct Eth<B: BlockT, C, P, CT, BE, H: ExHashT, A: ChainApi, EC: EthConfig<B
 	/// When using eth_call/eth_estimateGas, the maximum allowed gas limit will be
 	/// block.gas_limit * execute_gas_limit_multiplier
 	execute_gas_limit_multiplier: u64,
+	forced_parent_hashes: Option<BTreeMap<H256, H256>>,
 	_marker: PhantomData<(B, BE, EC)>,
 }
 
@@ -106,6 +107,7 @@ impl<B: BlockT, C, P, CT, BE, H: ExHashT, A: ChainApi> Eth<B, C, P, CT, BE, H, A
 		fee_history_cache: FeeHistoryCache,
 		fee_history_cache_limit: FeeHistoryCacheLimit,
 		execute_gas_limit_multiplier: u64,
+		forced_parent_hashes: Option<BTreeMap<H256, H256>>,
 	) -> Self {
 		Self {
 			client,
@@ -121,6 +123,7 @@ impl<B: BlockT, C, P, CT, BE, H: ExHashT, A: ChainApi> Eth<B, C, P, CT, BE, H, A
 			fee_history_cache,
 			fee_history_cache_limit,
 			execute_gas_limit_multiplier,
+			forced_parent_hashes,
 			_marker: PhantomData,
 		}
 	}
@@ -144,6 +147,7 @@ impl<B: BlockT, C, P, CT, BE, H: ExHashT, A: ChainApi, EC: EthConfig<B, C>>
 			fee_history_cache,
 			fee_history_cache_limit,
 			execute_gas_limit_multiplier,
+			forced_parent_hashes,
 			_marker: _,
 		} = self;
 
@@ -161,6 +165,7 @@ impl<B: BlockT, C, P, CT, BE, H: ExHashT, A: ChainApi, EC: EthConfig<B, C>>
 			fee_history_cache,
 			fee_history_cache_limit,
 			execute_gas_limit_multiplier,
+			forced_parent_hashes,
 			_marker: PhantomData,
 		}
 	}

template/node/src/rpc/eth.rs

@@ -1,4 +1,4 @@
-use std::sync::Arc;
+use std::{collections::BTreeMap, sync::Arc};
 
 use jsonrpsee::RpcModule;
 // Substrate
@@ -13,6 +13,7 @@ use sc_transaction_pool_api::TransactionPool;
 use sp_api::{CallApiAt, ProvideRuntimeApi};
 use sp_block_builder::BlockBuilder as BlockBuilderApi;
 use sp_blockchain::{Error as BlockChainError, HeaderBackend, HeaderMetadata};
+use sp_core::H256;
 use sp_runtime::traits::Block as BlockT;
 // Frontier
 use fc_db::Backend as FrontierBackend;
@@ -54,6 +55,8 @@ pub struct EthDeps<C, P, A: ChainApi, CT, B: BlockT> {
 	/// Maximum allowed gas limit will be ` block.gas_limit * execute_gas_limit_multiplier` when
 	/// using eth_call/eth_estimateGas.
 	pub execute_gas_limit_multiplier: u64,
+	/// Mandated parent hashes for a given block hash.
+	pub forced_parent_hashes: Option<BTreeMap<H256, H256>>,
 }
 
 impl<C, P, A: ChainApi, CT: Clone, B: BlockT> Clone for EthDeps<C, P, A, CT, B> {
@@ -74,6 +77,7 @@ impl<C, P, A: ChainApi, CT: Clone, B: BlockT> Clone for EthDeps<C, P, A, CT, B>
 			fee_history_cache: self.fee_history_cache.clone(),
 			fee_history_cache_limit: self.fee_history_cache_limit,
 			execute_gas_limit_multiplier: self.execute_gas_limit_multiplier,
+			forced_parent_hashes: self.forced_parent_hashes.clone(),
 		}
 	}
 }
@@ -119,6 +123,7 @@ where
 		fee_history_cache,
 		fee_history_cache_limit,
 		execute_gas_limit_multiplier,
+		forced_parent_hashes,
 	} = deps;
 
 	let mut signers = Vec::new();
@@ -141,6 +146,7 @@ where
 			fee_history_cache,
 			fee_history_cache_limit,
 			execute_gas_limit_multiplier,
+			forced_parent_hashes,
 		)
 		.replace_config::<EC>()
 		.into_rpc(),

template/node/src/service.rs

@@ -366,6 +366,7 @@ where
 		fee_history_cache: fee_history_cache.clone(),
 		fee_history_cache_limit,
 		execute_gas_limit_multiplier: eth_config.execute_gas_limit_multiplier,
+		forced_parent_hashes: None,
 	};
 
 	let rpc_builder = {