Merge pull request #47 from ethereumjs/multiple-hardfork-support

Validate blocks correctly for all known hardforks

Author: holgerd77

header.js

@@ -105,33 +105,48 @@ var BlockHeader = module.exports = function (data, opts) {
  */
 BlockHeader.prototype.canonicalDifficulty = function (parentBlock) {
   const hardfork = this._common.hardfork() || this._common.activeHardfork(utils.bufferToInt(this.number))
-
-  if (!this._common.hardforkGteHardfork(hardfork, 'byzantium')) {
-    throw new Error('Difficulty validation only supported on blocks >= byzantium')
-  }
-
   const blockTs = new BN(this.timestamp)
   const parentTs = new BN(parentBlock.header.timestamp)
   const parentDif = new BN(parentBlock.header.difficulty)
   const minimumDifficulty = new BN(this._common.param('pow', 'minimumDifficulty', hardfork))
   var offset = parentDif.div(new BN(this._common.param('pow', 'difficultyBoundDivisor', hardfork)))
+  var num = new BN(this.number)
+  var a
+  var cutoff
   var dif
 
-  // Byzantium
-  // max((2 if len(parent.uncles) else 1) - ((timestamp - parent.timestamp) // 9), -99)
-  var uncleAddend = parentBlock.header.uncleHash.equals(utils.SHA3_RLP_ARRAY) ? 1 : 2
-  var a = blockTs.sub(parentTs).idivn(9).ineg().iaddn(uncleAddend)
-  var cutoff = new BN(-99)
-  // MAX(cutoff, a)
-  if (cutoff.cmp(a) === 1) {
-    a = cutoff
-  }
-  dif = parentDif.add(offset.mul(a))
+  if (this._common.hardforkGteHardfork(hardfork, 'byzantium')) {
+    // max((2 if len(parent.uncles) else 1) - ((timestamp - parent.timestamp) // 9), -99)
+    var uncleAddend = parentBlock.header.uncleHash.equals(utils.SHA3_RLP_ARRAY) ? 1 : 2
+    a = blockTs.sub(parentTs).idivn(9).ineg().iaddn(uncleAddend)
+    cutoff = new BN(-99)
+    // MAX(cutoff, a)
+    if (cutoff.cmp(a) === 1) {
+      a = cutoff
+    }
+    dif = parentDif.add(offset.mul(a))
 
-  // Byzantium difficulty bomb delay
-  var num = new BN(this.number).isubn(3000000)
-  if (num.ltn(0)) {
-    num = new BN(0)
+    // Byzantium difficulty bomb delay
+    num.isubn(3000000)
+    if (num.ltn(0)) {
+      num = new BN(0)
+    }
+  } else if (this._common.hardforkGteHardfork(hardfork, 'homestead')) {
+    // 1 - (block_timestamp - parent_timestamp) // 10
+    a = blockTs.sub(parentTs).idivn(10).ineg().iaddn(1)
+    cutoff = new BN(-99)
+    // MAX(cutoff, a)
+    if (cutoff.cmp(a) === 1) {
+      a = cutoff
+    }
+    dif = parentDif.add(offset.mul(a))
+  } else {
+    // pre-homestead
+    if (parentTs.addn(this._common.param('pow', 'durationLimit', hardfork)).cmp(blockTs) === 1) {
+      dif = offset.add(parentDif)
+    } else {
+      dif = parentDif.sub(offset)
+    }
   }
 
   var exp = num.idivn(100000).isubn(2)

tests/difficulty.js

@@ -13,14 +13,6 @@ function normalize (data) {
 }
 
 tape('[Header]: difficulty tests', t => {
-  t.test('should test error cases', function (st) {
-    var parentBlock = new Block(null, { 'chain': 'mainnet', 'hardfork': 'spuriousDragon' })
-    var block = new Block(null, { 'chain': 'mainnet', 'hardfork': 'spuriousDragon' })
-
-    t.throws(function () { block.header.canonicalDifficulty(parentBlock) }, /Difficulty validation only supported on blocks >= byzantium$/, 'should throw on block with spuriousDragon HF initialization')
-    st.end()
-  })
-
   function runDifficultyTests (test, parentBlock, block, msg) {
     normalize(test)
 
@@ -29,42 +21,51 @@ tape('[Header]: difficulty tests', t => {
     t.assert(block.header.validateDifficulty(parentBlock), `test validateDifficulty (${msg})`)
   }
 
-  const testData = require('./testdata-difficulty.json')
-  for (let testName in testData) {
-    let test = testData[testName]
-    let parentBlock = new Block(null, { 'chain': 'mainnet', 'hardfork': 'byzantium' })
-    parentBlock.header.timestamp = test.parentTimestamp
-    parentBlock.header.difficulty = test.parentDifficulty
-    parentBlock.header.uncleHash = test.parentUncles
+  const hardforkTestData = {
+    'chainstart': require('./difficultyFrontier.json'),
+    'homestead': require('./difficultyHomestead.json'),
+    'byzantium': require('./difficultyByzantium.json')
+  }
+  for (let hardfork in hardforkTestData) {
+    const testData = hardforkTestData[hardfork]
+    for (let testName in testData) {
+      let test = testData[testName]
+      let parentBlock = new Block(null, { 'chain': 'mainnet', 'hardfork': hardfork })
+      parentBlock.header.timestamp = test.parentTimestamp
+      parentBlock.header.difficulty = test.parentDifficulty
+      parentBlock.header.uncleHash = test.parentUncles
 
-    let block = new Block(null, { 'chain': 'mainnet', 'hardfork': 'byzantium' })
-    block.header.timestamp = test.currentTimestamp
-    block.header.difficulty = test.currentDifficulty
-    block.header.number = test.currentBlockNumber
+      let block = new Block(null, { 'chain': 'mainnet', 'hardfork': hardfork })
+      block.header.timestamp = test.currentTimestamp
+      block.header.difficulty = test.currentDifficulty
+      block.header.number = test.currentBlockNumber
 
-    runDifficultyTests(test, parentBlock, block, 'fork determination by hardfork param')
+      runDifficultyTests(test, parentBlock, block, 'fork determination by hardfork param')
+    }
   }
 
-  for (let testName in testData) {
-    let test = testData[testName]
-    const BYZANTIUM_BLOCK = 4370000
-    let parentBlock = new Block()
-    parentBlock.header.timestamp = test.parentTimestamp
-    parentBlock.header.difficulty = test.parentDifficulty
-    parentBlock.header.uncleHash = test.parentUncles
-    parentBlock.header.number = utils.intToBuffer(BYZANTIUM_BLOCK - 1)
+  const chainTestData = {
+    'mainnet': require('./difficultyMainNetwork.json'),
+    'ropsten': require('./difficultyRopsten.json')
+  }
+  for (let chain in chainTestData) {
+    const testData = chainTestData[chain]
+    for (let testName in testData) {
+      let test = testData[testName]
+      let parentBlock = new Block(null, { 'chain': chain })
+      parentBlock.header.timestamp = test.parentTimestamp
+      parentBlock.header.difficulty = test.parentDifficulty
+      parentBlock.header.uncleHash = test.parentUncles
 
-    let block = new Block()
-    block.header.timestamp = test.currentTimestamp
-    block.header.difficulty = test.currentDifficulty
-    block.header.number = test.currentBlockNumber
+      let block = new Block(null, { 'chain': chain })
+      block.header.timestamp = test.currentTimestamp
+      block.header.difficulty = test.currentDifficulty
+      block.header.number = test.currentBlockNumber
 
-    if (utils.bufferToInt(block.header.number) >= BYZANTIUM_BLOCK) {
       runDifficultyTests(test, parentBlock, block, 'fork determination by block number')
-    } else {
-      t.throws(function () { block.header.canonicalDifficulty(parentBlock) }, /Difficulty validation only supported on blocks >= byzantium$/, 'should throw on block < byzantium')
     }
   }
+
   t.end()
 
   // Temporarily run local test selection