Implement debug_setHead

packages/client/src/rpc/modules/debug.ts

@@ -148,6 +148,9 @@
       1,
       [[validators.hex]],
     )
+    this.setHead = middleware(callWithStackTrace(this.setHead.bind(this), this._rpcDebug), 1, [
+      [validators.blockOption],
+    ])
     this.verbosity = middleware(callWithStackTrace(this.verbosity.bind(this), this._rpcDebug), 1, [
       [validators.unsignedInteger],
     ])
@@ -457,4 +460,35 @@
     this.client.config.logger.configure({ level: logLevels[level] })
     return `level: ${this.client.config.logger.level}`
   }
+
+  /**
+   * Sets the current head of the local chain by block number. Note, this is a
+   * destructive action and may severely damage your chain. Use with extreme
+   * caution.
+   * @param blockOpt Block number or tag to set as head of chain
+   */
+  async setHead(params: [string]) {
+    const [blockOpt] = params
+    if (blockOpt === 'pending') {
+      throw {
+        code: INVALID_PARAMS,
+        message: `"pending" is not supported`,
+      }
+    }
+
+    let headHash = await this.service.skeleton?.headHash()
+    const oldHead = headHash ? bytesToHex(headHash!) : undefined
+    const block = await getBlockByOption(blockOpt, this.chain)
+    try {
+      await this.service.skeleton?.setHead(block, true)
+    } catch {
+      throw {
+        code: INTERNAL_ERROR,
+      }
+    }
+    headHash = await this.service.skeleton?.headHash()
+    const newHead = headHash ? bytesToHex(headHash!) : undefined
+
+    return `oldHead: ${oldHead} - newHead: ${newHead}`
+  }
 }

packages/client/test/rpc/debug/setHead.spec.ts

@@ -0,0 +1,41 @@
+import { bigIntToHex } from '@ethereumjs/util'
+import { assert, describe, it } from 'vitest'
+
+import { createClient, createManager, getRPCClient, startRPC } from '../helpers.js'
+
+import { generateBlockchain, generateConsecutiveBlock } from './util.js'
+
+const method = 'debug_setHead'
+
+describe(method, async () => {
+  it('call with valid arguments', async () => {
+    const { blockchain, blocks, _ } = await generateBlockchain(3)
+    const a = await createClient({ blockchain })
+    await a.service.skeleton?.open()
+    const manager = createManager(a)
+    const rpc = getRPCClient(startRPC(manager.getMethods()))
+
+    assert.equal(
+      await a.service.skeleton?.headHash(),
+      undefined,
+      'should return undefined when head is not set',
+    )
+    for (let i = 0; i < blocks.length; i++) {
+      await rpc.request(method, [`0x${i}`])
+      assert.deepEqual(
+        await a.service.skeleton?.headHash()!,
+        await blocks[i].header.hash(),
+        `should return hash of block number ${i} set as head`,
+      )
+    }
+
+    const newCanonicalHead = generateConsecutiveBlock(blocks[2], 1)
+    await blockchain.putBlocks([newCanonicalHead])
+    await rpc.request(method, [bigIntToHex(newCanonicalHead.header.number)])
+    assert.deepEqual(
+      await a.service.skeleton?.headHash()!,
+      newCanonicalHead.header.hash(),
+      `should set hash to new head when there is a fork`,
+    )
+  }, 30000)
+})

packages/client/test/rpc/debug/util.ts

@@ -0,0 +1,96 @@
+import { Block, createBlock, createBlockHeader } from '@ethereumjs/block'
+import { createBlockchain } from '@ethereumjs/blockchain'
+import { Common, Hardfork, Mainnet } from '@ethereumjs/common'
+
+export const generateBlocks = (numberOfBlocks: number, existingBlocks?: Block[]): Block[] => {
+  const blocks = existingBlocks ? existingBlocks : []
+
+  const gasLimit = 8000000
+  const common = new Common({ chain: Mainnet, hardfork: Hardfork.Chainstart })
+  const opts = { common }
+
+  if (blocks.length === 0) {
+    const genesis = createBlock({ header: { gasLimit } }, opts)
+    blocks.push(genesis)
+  }
+
+  for (let i = blocks.length; i < numberOfBlocks; i++) {
+    const lastBlock = blocks[i - 1]
+    const blockData = {
+      header: {
+        number: i,
+        parentHash: lastBlock.hash(),
+        gasLimit,
+        timestamp: lastBlock.header.timestamp + BigInt(1),
+      },
+    }
+    const block = createBlock(blockData, {
+      common,
+      calcDifficultyFromHeader: lastBlock.header,
+    })
+    blocks.push(block)
+  }
+
+  return blocks
+}
+
+export const generateBlockchain = async (numberOfBlocks: number, genesis?: Block): Promise<any> => {
+  const existingBlocks: Block[] = genesis ? [genesis] : []
+  const blocks = generateBlocks(numberOfBlocks, existingBlocks)
+
+  const blockchain = await createBlockchain({
+    validateBlocks: true,
+    genesisBlock: genesis ?? blocks[0],
+  })
+  try {
+    await blockchain.putBlocks(blocks.slice(1))
+  } catch (error: any) {
+    return { error }
+  }
+
+  return {
+    blockchain,
+    blocks,
+    error: null,
+  }
+}
+/**
+ *
+ * @param parentBlock parent block to generate the consecutive block on top of
+ * @param difficultyChangeFactor this integer can be any value, but will only return unique blocks between [-99, 1] (this is due to difficulty calculation). 1 will increase the difficulty, 0 will keep the difficulty constant any any negative number will decrease the difficulty
+ */
+
+export const generateConsecutiveBlock = (
+  parentBlock: Block,
+  difficultyChangeFactor: number,
+  gasLimit: bigint = BigInt(8000000),
+): Block => {
+  if (difficultyChangeFactor > 1) {
+    difficultyChangeFactor = 1
+  }
+  const common = new Common({ chain: Mainnet, hardfork: Hardfork.MuirGlacier })
+  const tmpHeader = createBlockHeader(
+    {
+      number: parentBlock.header.number + BigInt(1),
+      timestamp: parentBlock.header.timestamp + BigInt(10 + -difficultyChangeFactor * 9),
+    },
+    { common },
+  )
+  const header = createBlockHeader(
+    {
+      number: parentBlock.header.number + BigInt(1),
+      parentHash: parentBlock.hash(),
+      gasLimit,
+      timestamp: parentBlock.header.timestamp + BigInt(10 + -difficultyChangeFactor * 9),
+      difficulty: tmpHeader.ethashCanonicalDifficulty(parentBlock.header),
+    },
+    {
+      common,
+      calcDifficultyFromHeader: parentBlock.header,
+    },
+  )
+
+  const block = new Block(header, undefined, undefined, undefined, { common }, undefined)
+
+  return block
+}