Add pending support for eth_getBlockByNumber (polkadot-evm#1048)

* Add `pending` support for `eth_getBlockByNumber`

* header not needed

* cleanup

* prettier

* update some fields to be optional on pending

* update test

* cleanup

client/rpc-core/src/types/block.rs

@@ -52,7 +52,7 @@ pub struct Block {
 	#[serde(flatten)]
 	pub header: Header,
 	/// Total difficulty
-	pub total_difficulty: U256,
+	pub total_difficulty: Option<U256>,
 	/// Uncles' hashes
 	pub uncles: Vec<H256>,
 	/// Transactions
@@ -78,7 +78,7 @@ pub struct Header {
 	/// Authors address
 	pub author: H160,
 	/// Alias of `author`
-	pub miner: H160,
+	pub miner: Option<H160>,
 	/// State root hash
 	pub state_root: H256,
 	/// Transactions root hash

client/rpc/src/eth/block.rs

@@ -23,6 +23,7 @@ use jsonrpsee::core::RpcResult;
 // Substrate
 use sc_client_api::backend::{Backend, StorageProvider};
 use sc_transaction_pool::ChainApi;
+use sc_transaction_pool_api::InPoolTransaction;
 use sp_api::ProvideRuntimeApi;
 use sp_blockchain::HeaderBackend;
 use sp_core::hashing::keccak_256;
@@ -43,6 +44,7 @@ where
 	C::Api: EthereumRuntimeRPCApi<B>,
 	C: HeaderBackend<B> + StorageProvider<B, BE> + 'static,
 	BE: Backend<B>,
+	A: ChainApi<Block = B> + 'static,
 {
 	pub async fn block_by_hash(&self, hash: H256, full: bool) -> RpcResult<Option<RichBlock>> {
 		let client = Arc::clone(&self.client);
@@ -77,6 +79,7 @@ where
 					Some(hash),
 					full,
 					base_fee,
+					false,
 				);
 
 				let substrate_hash = H256::from_slice(substrate_hash.as_ref());
@@ -102,52 +105,97 @@ where
 		let client = Arc::clone(&self.client);
 		let block_data_cache = Arc::clone(&self.block_data_cache);
 		let backend = Arc::clone(&self.backend);
+		let graph = Arc::clone(&self.graph);
 
-		let id = match frontier_backend_client::native_block_id::<B, C>(
+		match frontier_backend_client::native_block_id::<B, C>(
 			client.as_ref(),
 			backend.as_ref(),
 			Some(number),
 		)? {
-			Some(id) => id,
-			None => return Ok(None),
-		};
-		let substrate_hash = client
-			.expect_block_hash_from_id(&id)
-			.map_err(|_| internal_err(format!("Expect block number from id: {}", id)))?;
+			Some(id) => {
+				let substrate_hash = client
+					.expect_block_hash_from_id(&id)
+					.map_err(|_| internal_err(format!("Expect block number from id: {}", id)))?;
 
-		let schema = fc_storage::onchain_storage_schema(client.as_ref(), substrate_hash);
+				let schema = fc_storage::onchain_storage_schema(client.as_ref(), substrate_hash);
 
-		let block = block_data_cache.current_block(schema, substrate_hash).await;
-		let statuses = block_data_cache
-			.current_transaction_statuses(schema, substrate_hash)
-			.await;
+				let block = block_data_cache.current_block(schema, substrate_hash).await;
+				let statuses = block_data_cache
+					.current_transaction_statuses(schema, substrate_hash)
+					.await;
 
-		let base_fee = client.runtime_api().gas_price(substrate_hash).ok();
+				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)));
+				match (block, statuses) {
+					(Some(block), Some(statuses)) => {
+						let hash = H256::from(keccak_256(&rlp::encode(&block.header)));
+						let mut rich_block = rich_block_build(
+							block,
+							statuses.into_iter().map(Option::Some).collect(),
+							Some(hash),
+							full,
+							base_fee,
+							false,
+						);
 
-				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
+						}
 
-				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),
 				}
+			}
+			None if number == BlockNumber::Pending => {
+				let api = client.runtime_api();
+				let best_hash = client.info().best_hash;
 
-				Ok(Some(rich_block))
+				// Get current in-pool transactions
+				let mut xts: Vec<<B as BlockT>::Extrinsic> = Vec::new();
+				// ready validated pool
+				xts.extend(
+					graph
+						.validated_pool()
+						.ready()
+						.map(|in_pool_tx| in_pool_tx.data().clone())
+						.collect::<Vec<<B as BlockT>::Extrinsic>>(),
+				);
+
+				// future validated pool
+				xts.extend(
+					graph
+						.validated_pool()
+						.futures()
+						.iter()
+						.map(|(_hash, extrinsic)| extrinsic.clone())
+						.collect::<Vec<<B as BlockT>::Extrinsic>>(),
+				);
+
+				let (block, statuses) = api
+					.pending_block(best_hash, xts)
+					.map_err(|_| internal_err(format!("Runtime access error at {}", best_hash)))?;
+
+				let base_fee = api.gas_price(best_hash).ok();
+
+				match (block, statuses) {
+					(Some(block), Some(statuses)) => Ok(Some(rich_block_build(
+						block,
+						statuses.into_iter().map(Option::Some).collect(),
+						None,
+						full,
+						base_fee,
+						true,
+					))),
+					_ => Ok(None),
+				}
 			}
-			_ => Ok(None),
+			None => Ok(None),
 		}
 	}
 

client/rpc/src/eth/mod.rs

@@ -396,17 +396,26 @@ fn rich_block_build(
 	hash: Option<H256>,
 	full_transactions: bool,
 	base_fee: Option<U256>,
+	is_pending: bool,
 ) -> RichBlock {
+	let (hash, miner, nonce, total_difficulty) = if !is_pending {
+		(
+			Some(hash.unwrap_or_else(|| H256::from(keccak_256(&rlp::encode(&block.header))))),
+			Some(block.header.beneficiary),
+			Some(block.header.nonce),
+			Some(U256::zero()),
+		)
+	} else {
+		(None, None, None, None)
+	};
 	Rich {
 		inner: Block {
 			header: Header {
-				hash: Some(
-					hash.unwrap_or_else(|| H256::from(keccak_256(&rlp::encode(&block.header)))),
-				),
+				hash,
 				parent_hash: block.header.parent_hash,
 				uncles_hash: block.header.ommers_hash,
 				author: block.header.beneficiary,
-				miner: block.header.beneficiary,
+				miner,
 				state_root: block.header.state_root,
 				transactions_root: block.header.transactions_root,
 				receipts_root: block.header.receipts_root,
@@ -417,10 +426,10 @@ fn rich_block_build(
 				logs_bloom: block.header.logs_bloom,
 				timestamp: U256::from(block.header.timestamp / 1000),
 				difficulty: block.header.difficulty,
-				nonce: Some(block.header.nonce),
+				nonce,
 				size: Some(U256::from(rlp::encode(&block.header).len() as u32)),
 			},
-			total_difficulty: U256::zero(),
+			total_difficulty,
 			uncles: vec![],
 			transactions: {
 				if full_transactions {

client/rpc/src/eth_pubsub.rs

@@ -107,7 +107,7 @@ impl EthSubscriptionResult {
 				parent_hash: block.header.parent_hash,
 				uncles_hash: block.header.ommers_hash,
 				author: block.header.beneficiary,
-				miner: block.header.beneficiary,
+				miner: Some(block.header.beneficiary),
 				state_root: block.header.state_root,
 				transactions_root: block.header.transactions_root,
 				receipts_root: block.header.receipts_root,

primitives/rpc/src/lib.rs

@@ -207,6 +207,10 @@ sp_api::decl_runtime_apis! {
 		/// Used to determine if gas limit multiplier for non-transactional calls (eth_call/estimateGas)
 		/// is supported.
 		fn gas_limit_multiplier_support();
+		/// Return the pending block.
+		fn pending_block(
+			xts: Vec<<Block as BlockT>::Extrinsic>,
+		) -> (Option<ethereum::BlockV2>, Option<Vec<TransactionStatus>>);
 	}
 
 	#[api_version(2)]

template/runtime/src/lib.rs

@@ -35,7 +35,7 @@ use frame_support::weights::constants::ParityDbWeight as RuntimeDbWeight;
 use frame_support::weights::constants::RocksDbWeight as RuntimeDbWeight;
 use frame_support::{
 	construct_runtime, parameter_types,
-	traits::{ConstU32, ConstU8, FindAuthor, OnTimestampSet},
+	traits::{ConstU32, ConstU8, FindAuthor, OnFinalize, OnTimestampSet},
 	weights::{constants::WEIGHT_REF_TIME_PER_MILLIS, ConstantMultiplier, IdentityFee, Weight},
 };
 use pallet_grandpa::{
@@ -759,6 +759,21 @@ impl_runtime_apis! {
 		}
 
 		fn gas_limit_multiplier_support() {}
+
+		fn pending_block(
+			xts: Vec<<Block as BlockT>::Extrinsic>,
+		) -> (Option<pallet_ethereum::Block>, Option<Vec<TransactionStatus>>) {
+			for ext in xts.into_iter() {
+				let _ = Executive::apply_extrinsic(ext);
+			}
+
+			Ethereum::on_finalize(System::block_number() + 1);
+
+			(
+				pallet_ethereum::CurrentBlock::<Runtime>::get(),
+				pallet_ethereum::CurrentTransactionStatuses::<Runtime>::get()
+			)
+		}
 	}
 
 	impl fp_rpc::ConvertTransactionRuntimeApi<Block> for Runtime {

ts-tests/tests/test-block.ts

@@ -1,8 +1,8 @@
 import { expect } from "chai";
 import { step } from "mocha-steps";
 
-import { BLOCK_TIMESTAMP, ETH_BLOCK_GAS_LIMIT } from "./config";
-import { createAndFinalizeBlock, describeWithFrontier } from "./util";
+import { BLOCK_TIMESTAMP, ETH_BLOCK_GAS_LIMIT, GENESIS_ACCOUNT, GENESIS_ACCOUNT_PRIVATE_KEY } from "./config";
+import { createAndFinalizeBlock, describeWithFrontier, customRequest } from "./util";
 
 describeWithFrontier("Frontier RPC (Block)", (context) => {
 	let previousBlock;
@@ -145,3 +145,53 @@ describeWithFrontier("Frontier RPC (Block)", (context) => {
 		expect(block.parentHash).to.equal(previousBlock.hash);
 	});
 });
+
+describeWithFrontier("Frontier RPC (Pending Block)", (context) => {
+	const TEST_ACCOUNT = "0x1111111111111111111111111111111111111111";
+
+	it("should return pending block", async function () {
+		var nonce = 0;
+		let sendTransaction = async () => {
+			const tx = await context.web3.eth.accounts.signTransaction(
+				{
+					from: GENESIS_ACCOUNT,
+					to: TEST_ACCOUNT,
+					value: "0x200", // Must be higher than ExistentialDeposit
+					gasPrice: "0x3B9ACA00",
+					gas: "0x100000",
+					nonce: nonce,
+				},
+				GENESIS_ACCOUNT_PRIVATE_KEY
+			);
+			nonce = nonce + 1;
+			return (await customRequest(context.web3, "eth_sendRawTransaction", [tx.rawTransaction])).result;
+		};
+
+		// block 1 send 5 transactions
+		const expectedXtsNumber = 5;
+		for (var _ of Array(expectedXtsNumber)) {
+			await sendTransaction();
+		}
+
+		// test still invalid future transactions can be safely applied (they are applied, just not overlayed)
+		nonce = nonce + 100;
+		await sendTransaction();
+
+		// do not seal, get pendign block
+		let pending_transactions = [];
+		{
+			const pending = (await customRequest(context.web3, "eth_getBlockByNumber", ["pending", false])).result;
+			expect(pending.hash).to.be.null;
+			expect(pending.miner).to.be.null;
+			expect(pending.nonce).to.be.null;
+			expect(pending.totalDifficulty).to.be.null;
+			pending_transactions = pending.transactions;
+			expect(pending_transactions.length).to.be.eq(expectedXtsNumber);
+		}
+
+		// seal and compare latest blocks transactions with the previously pending
+		await createAndFinalizeBlock(context.web3);
+		const latest_block = await context.web3.eth.getBlock("latest", false);
+		expect(pending_transactions).to.be.deep.eq(latest_block.transactions);
+	});
+});