Make usage of delegate list BFT compliant - Closes #3681

framework/src/controller/schema/application_config_schema.js

@@ -87,6 +87,7 @@ module.exports = {
 						'EPOCH_TIME',
 						'BLOCK_TIME',
 						'MAX_TRANSACTIONS_PER_BLOCK',
+						'DELEGATE_LIST_ROUND_OFFSET',
 						'REWARDS',
 					],
 					properties: {
@@ -111,6 +112,12 @@ module.exports = {
 							maximum: 150,
 							description: 'Maximum number of transactions allowed per block',
 						},
+						DELEGATE_LIST_ROUND_OFFSET: {
+							type: 'number',
+							minimum: 0,
+							description:
+								'Number of rounds before in which the list of delegates will be used for the current round - i.e. The set of active delegates that will be chosen to forge during round `r` will be taken from the list generated in the end of round `r - DELEGATE_LIST_ROUND_OFFSET`',
+						},
 						REWARDS: {
 							id: 'rewards',
 							type: 'object',
@@ -186,6 +193,7 @@ module.exports = {
 				EPOCH_TIME: new Date(Date.UTC(2016, 4, 24, 17, 0, 0, 0)).toISOString(),
 				BLOCK_TIME: 10,
 				MAX_TRANSACTIONS_PER_BLOCK: 25,
+				DELEGATE_LIST_ROUND_OFFSET: 2,
 				REWARDS: {
 					MILESTONES: [
 						'500000000', // Initial Reward

framework/src/modules/chain/block_processor_v0.js

@@ -110,6 +110,7 @@ const validateSchema = ({ block }) => {
 class BlockProcessorV0 extends BaseBlockProcessor {
 	constructor({ blocksModule, dposModule, logger, constants, exceptions }) {
 		super();
+		const delegateListRoundOffset = 0;
 		this.blocksModule = blocksModule;
 		this.dposModule = dposModule;
 		this.logger = logger;
@@ -132,7 +133,8 @@ class BlockProcessorV0 extends BaseBlockProcessor {
 					blockBytes,
 				}), // validate common block header
 			data => this.blocksModule.verifyInMemory(data),
-			({ block }) => this.dposModule.verifyBlockForger(block),
+			({ block }) =>
+				this.dposModule.verifyBlockForger(block, { delegateListRoundOffset }),
 		]);
 
 		this.validateDetached.pipe([
@@ -155,11 +157,23 @@ class BlockProcessorV0 extends BaseBlockProcessor {
 
 		this.verify.pipe([data => this.blocksModule.verify(data)]);
 
-		this.apply.pipe([data => this.blocksModule.apply(data)]);
+		this.apply.pipe([
+			data => this.blocksModule.apply(data),
+			({ block, tx }) =>
+				this.dposModule.apply(block, { tx, delegateListRoundOffset }),
+		]);
 
-		this.applyGenesis.pipe([data => this.blocksModule.applyGenesis(data)]);
+		this.applyGenesis.pipe([
+			data => this.blocksModule.applyGenesis(data),
+			({ block, tx }) =>
+				this.dposModule.apply(block, { tx, delegateListRoundOffset }),
+		]);
 
-		this.undo.pipe([data => this.blocksModule.undo(data)]);
+		this.undo.pipe([
+			data => this.blocksModule.undo(data),
+			({ block, tx }) =>
+				this.dposModule.undo(block, { tx, delegateListRoundOffset }),
+		]);
 
 		this.create.pipe([data => this._create(data)]);
 	}

framework/src/modules/chain/block_processor_v2.js

@@ -174,7 +174,6 @@ class BlockProcessorV2 extends BaseBlockProcessor {
 		exceptions,
 	}) {
 		super();
-		const verifyBlockForgerOffset = 2;
 		this.blocksModule = blocksModule;
 		this.bftModule = bftModule;
 		this.dposModule = dposModule;
@@ -204,8 +203,7 @@ class BlockProcessorV2 extends BaseBlockProcessor {
 					blockBytes,
 				}), // validate common block header
 			data => this.blocksModule.verifyInMemory(data),
-			({ block }) =>
-				this.dposModule.verifyBlockForger(block, verifyBlockForgerOffset),
+			({ block }) => this.dposModule.verifyBlockForger(block),
 			({ block }) => this.bftModule.validateBlock(block),
 		]);
 
@@ -232,13 +230,18 @@ class BlockProcessorV2 extends BaseBlockProcessor {
 		this.apply.pipe([
 			data => this.blocksModule.verify(data),
 			data => this.blocksModule.apply(data),
+			({ block, tx }) => this.dposModule.apply(block, { tx }),
 			({ block, tx }) => this.bftModule.addNewBlock(block, tx),
 		]);
 
-		this.applyGenesis.pipe([data => this.blocksModule.applyGenesis(data)]);
+		this.applyGenesis.pipe([
+			data => this.blocksModule.applyGenesis(data),
+			({ block, tx }) => this.dposModule.apply(block, { tx }),
+		]);
 
 		this.undo.pipe([
 			data => this.blocksModule.undo(data),
+			({ block, tx }) => this.dposModule.undo(block, { tx }),
 			({ block }) => this.bftModule.deleteBlocks([block]),
 		]);
 

framework/src/modules/chain/blocks/blocks.js

@@ -36,8 +36,7 @@ const {
 	deleteLastBlock,
 	deleteFromBlockId,
 	undoConfirmedStep,
-	saveBlockStep,
-	undoBlockStep,
+	saveBlock,
 } = require('./chain');
 const {
 	calculateSupply,
@@ -69,7 +68,6 @@ class Blocks extends EventEmitter {
 		slots,
 		exceptions,
 		// Modules
-		dposModule,
 		interfaceAdapters,
 		// constants
 		blockReceiptTimeout, // set default
@@ -100,7 +98,6 @@ class Blocks extends EventEmitter {
 
 		this.logger = logger;
 		this.storage = storage;
-		this.dposModule = dposModule;
 		this.exceptions = exceptions;
 		this.genesisBlock = genesisBlock;
 		this.interfaceAdapters = interfaceAdapters;
@@ -327,6 +324,8 @@ class Blocks extends EventEmitter {
 			this.exceptions,
 			tx,
 		);
+
+		this._lastBlock = block;
 	}
 
 	async applyGenesis({ block, tx }) {
@@ -337,6 +336,12 @@ class Blocks extends EventEmitter {
 			this.exceptions,
 			tx,
 		);
+
+		this._lastBlock = block;
+	}
+
+	async save({ blockJSON, tx }) {
+		await saveBlock(this.storage, blockJSON, tx);
 	}
 
 	async undo({ block, tx }) {
@@ -347,20 +352,6 @@ class Blocks extends EventEmitter {
 			this.exceptions,
 			tx,
 		);
-
-		await undoBlockStep(this.dposModule, block, tx);
-	}
-
-	async save({ block, blockJSON, tx, skipSave }) {
-		await saveBlockStep(
-			this.storage,
-			this.dposModule,
-			block,
-			blockJSON,
-			skipSave,
-			tx,
-		);
-		this._lastBlock = block;
 	}
 
 	async remove({ block, blockJSON, tx }, saveTempBlock = false) {

framework/src/modules/chain/blocks/chain.js

@@ -184,32 +184,6 @@ const applyConfirmedGenesisStep = async (
 	return block;
 };
 
-/**
- * Calls saveBlock for the block and performs round tick
- *
- * @private
- * @param {Object} storage - Storage component with write methods
- * @param {Object} dposModule - Dpos module class
- * @param {Object} block - Block object
- * @param {boolean} skipSave - Flag to save block into database
- * @param {function} tx - Database transaction for atomic operations
- * @returns {Promise<reject|resolve>}
- */
-const saveBlockStep = async (
-	storage,
-	dposModule,
-	block,
-	blockJSON,
-	skipSave,
-	tx,
-) => {
-	if (!skipSave) {
-		await saveBlock(storage, blockJSON, tx);
-	}
-
-	await dposModule.apply(block, tx);
-};
-
 /**
  * Reverts confirmed transactions due to block deletion
  * @param {Object} block - secondLastBlock
@@ -245,21 +219,11 @@ const undoConfirmedStep = async (storage, slots, block, exceptions, tx) => {
 	await stateStore.account.finalize();
 };
 
-/**
- * Revert given block
- * @param {Object} block - block to be undone
- * @param {Object} tx - database transaction
- */
-const undoBlockStep = async (dposModule, block, tx) =>
-	dposModule.undo(block, tx);
-
 module.exports = {
 	saveBlock,
-	undoBlockStep,
 	saveBlockBatch,
 	deleteLastBlock,
 	deleteFromBlockId,
-	saveBlockStep,
 	applyConfirmedStep,
 	applyConfirmedGenesisStep,
 	undoConfirmedStep,

framework/src/modules/chain/chain.js

@@ -416,6 +416,8 @@ module.exports = class Chain {
 			logger: this.logger,
 			slots: this.slots,
 			activeDelegates: this.options.constants.ACTIVE_DELEGATES,
+			delegateListRoundOffset: this.options.constants
+				.DELEGATE_LIST_ROUND_OFFSET,
 			exceptions: this.options.exceptions,
 		});
 
@@ -430,7 +432,6 @@ module.exports = class Chain {
 			genesisBlock: this.options.genesisBlock,
 			slots: this.slots,
 			exceptions: this.options.exceptions,
-			dposModule: this.dpos,
 			interfaceAdapters: this.interfaceAdapters,
 			blockReceiptTimeout: this.options.constants.BLOCK_RECEIPT_TIMEOUT,
 			loadPerIteration: 1000,
@@ -468,7 +469,7 @@ module.exports = class Chain {
 			logger: this.logger,
 			slots: this.slots,
 			blocks: this.blocks,
-			dpos: {},
+			dposModule: this.dpos,
 			activeDelegates: this.options.constants.ACTIVE_DELEGATES,
 		});
 

framework/src/modules/chain/dpos/delegates_info.js

@@ -67,7 +67,7 @@ class DelegatesInfo {
 		this.exceptions = exceptions;
 	}
 
-	async apply(block, tx) {
+	async apply(block, { tx, delegateListRoundOffset }) {
 		const undo = false;
 
 		/**
@@ -80,30 +80,33 @@ class DelegatesInfo {
 			return false;
 		}
 
-		return this._update(block, undo, tx);
+		return this._update(block, { undo, tx, delegateListRoundOffset });
 	}
 
-	async undo(block, tx) {
+	async undo(block, { tx, delegateListRoundOffset }) {
 		const undo = true;
 
 		// Never undo genesis block
 		if (_isGenesisBlock(block)) {
 			throw new Error('Cannot undo genesis block');
 		}
-		return this._update(block, undo, tx);
+		return this._update(block, { undo, tx, delegateListRoundOffset });
 	}
 
 	/**
 	 * @param {Block} block
 	 */
-	async _update(block, undo, tx) {
+	async _update(block, { undo, tx, delegateListRoundOffset }) {
 		await this._updateProducedBlocks(block, undo, tx);
 
 		// Perform updates that only happens in the end of the round
 		if (this._isLastBlockOfTheRound(block)) {
 			const round = this.slots.calcRound(block.height);
 
-			const roundSummary = await this._summarizeRound(block, tx);
+			const roundSummary = await this._summarizeRound(block, {
+				tx,
+				delegateListRoundOffset,
+			});
 
 			await Promise.all([
 				this._updateMissedBlocks(roundSummary, undo, tx),
@@ -239,7 +242,7 @@ class DelegatesInfo {
 	 * @returns {Object} { earnings: { fee, reward } }
 	 * @returns {Object} { delegateAccount: AccountEntity }
 	 */
-	async _summarizeRound(block, tx) {
+	async _summarizeRound(block, { tx, delegateListRoundOffset }) {
 		const round = this.slots.calcRound(block.height);
 		this.logger.debug('Calculating rewards and fees for round: ', round);
 
@@ -293,6 +296,7 @@ class DelegatesInfo {
 
 			return {
 				round,
+				delegateListRoundOffset,
 				totalFee,
 				uniqForgersInfo,
 			};
@@ -302,9 +306,14 @@ class DelegatesInfo {
 		}
 	}
 
-	async _getMissedBlocksDelegatePublicKeys({ round, uniqForgersInfo }) {
+	async _getMissedBlocksDelegatePublicKeys({
+		round,
+		delegateListRoundOffset,
+		uniqForgersInfo,
+	}) {
 		const expectedForgingPublicKeys = await this.delegatesList.getForgerPublicKeysForRound(
 			round,
+			delegateListRoundOffset,
 		);
 
 		return expectedForgingPublicKeys.filter(

framework/src/modules/chain/dpos/delegates_list.js

@@ -45,12 +45,16 @@ class DelegatesList {
 	}
 
 	/**
-	 * Get shuffled list of active delegate public keys for a specific round -> forger public keys
+	 * Get shuffled list of active delegate public keys (forger public keys) for a specific round.
+	 * The list of delegates used is the one computed at the end of the round `r - delegateListRoundOffset`
 	 * @param {number} round
+	 * @param {number} delegateListRoundOffset
 	 */
-	async getForgerPublicKeysForRound(round) {
+	async getForgerPublicKeysForRound(round, delegateListRoundOffset) {
+		// Delegate list is generated from round 1 hence `roundWithOffset` can't be less than 1
+		const roundWithOffset = Math.max(round - delegateListRoundOffset, 1);
 		const delegatePublicKeys = await this.storage.entities.RoundDelegates.getActiveDelegatesForRound(
-			round,
+			roundWithOffset,
 		);
 
 		if (!delegatePublicKeys.length) {
@@ -124,18 +128,18 @@ class DelegatesList {
 	 * Validates if block was forged by correct delegate
 	 *
 	 * @param {Object} block
-	 * @param {Number} roundOffset - use delegate list generated at the end of `roundOffset` before the current round
+	 * @param {Number} delegateListRoundOffset - use delegate list generated at the end of `delegateListRoundOffset` before the current round
 	 * @return {Boolean} - `true`
 	 * @throw {Error} Failed to verify slot
 	 */
-	async verifyBlockForger(block, roundOffset) {
+	async verifyBlockForger(block, delegateListRoundOffset) {
 		const currentSlot = this.slots.getSlotNumber(block.timestamp);
 		const currentRound = this.slots.calcRound(block.height);
 
-		// Delegate list is generated from round 1 hence `roundToVerify` can't be less than 1
-		const roundToVerify = Math.max(currentRound - roundOffset, 1);
-
-		const delegateList = await this.getForgerPublicKeysForRound(roundToVerify);
+		const delegateList = await this.getForgerPublicKeysForRound(
+			currentRound,
+			delegateListRoundOffset,
+		);
 
 		if (!delegateList.length) {
 			throw new Error(
@@ -160,7 +164,7 @@ class DelegatesList {
 			 * Should be tackled by https://github.com/LiskHQ/lisk-sdk/issues/4194
 			 */
 			const { ignoreDelegateListCacheForRounds = [] } = this.exceptions;
-			if (ignoreDelegateListCacheForRounds.includes(roundToVerify)) {
+			if (ignoreDelegateListCacheForRounds.includes(currentRound)) {
 				return true;
 			}