Client: Add debugCode CLI option to generate Block execution script

[holgerd77]

Fixing #1090

I will actually not start working on new consensus bugs without adding a new meaningful debug tool. 😂

This one from this first commit 8d0afb7 is actually super-handy: it adds a new CLI option (mainly for internal usage, but of course also can be leveraged by consumers) debugCode which generates a dynamic script on a VM block execution failure.

So this can be run with:

npm run client:start -- --network=rinkeby --debugCode

Script looks something like this and will be logged out to the console:

/**
 * Script for locally executing a block in the EthereumJS VM,
 * meant to be used from packages/vm directory within the
 * https://github.com/ethereumjs/ethereumjs-monorepo repository.
 *
 * Block: 14182
 * Hardfork: spuriousDragon
 *
 * Run with: DEBUG=vm:*:*,vm:*,-vm:ops:* ts-node [SCRIPT_NAME].ts
 *
 */

const level = require('level')
import Common from '@ethereumjs/common'
import { Block } from '@ethereumjs/block'
import VM from './lib'
import { SecureTrie as Trie } from '@ethereumjs/trie'
import { DefaultStateManager } from './lib/state'
import Blockchain from '@ethereumjs/blockchain'

const main = async () => {
  const common = new Common({ chain: 'rinkeby', hardfork: 'spuriousDragon' })
  const block = Block.fromRLPSerializedBlock(Buffer.from('f91692f9025ba0b477241819c2222f...', 'hex'), { common })

  const stateDB = level('/Ethereum/ethereumjs/rinkeby/state')
  const trie = new Trie(stateDB)
  const stateManager = new DefaultStateManager({ trie, common })
  // Ensure we run on the right root
  stateManager.setStateRoot(Buffer.from('135fae6d4909a072d77707a797769afc72f6239a72173e0f411c7700af66ac26', 'hex'))


  const chainDB = level('/Ethereum/ethereumjs/rinkeby/chain')
  const blockchain = await Blockchain.create({
    db: chainDB,
    common,
    validateBlocks: true,
    validateConsensus: false,
  })
  const vm = new VM({ stateManager, blockchain, common })

  await vm.runBlock({ block })
}

main()

The script works out of the box, has all the correct values filled in (HFs, directories, block RLP) and can directly be copied over into the VM folder and then executed to reliably reproduce the error locally. 😄

[codecov]

Codecov Report

Merging #1091 (0d83ea9) into master (6822c08) will decrease coverage by 4.20%.
The diff coverage is n/a.

Flag	Coverage Δ
block	79.02% <ø> (-2.24%)	⬇️
blockchain	?
client	?
common	?
ethash	?
tx	?
vm	82.32% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

[jochem-brouwer]

Hi @holgerd77, please check this PR #1093. I wanted to fetch the Geth JSON trace from an archive node, but sadly the eth dev ops node seems to be down.

I am currently spinning up a Rinkeby archive node to get the trace. I'll upload it to the PR, so you can directly compare traces and see exactly at which point the two transactions diverge 😄

[holgerd77]

@jochem-brouwer great 👍

[jochem-brouwer]

Will merge the debug stuff here (you can remove these debug files later when ready for review) so we can compare stack traces.

[holgerd77]

@jochem-brouwer Ok. 😄

The CI got stuck at some point, I will merge this in by admin merge so that we can continue.

[jochem-brouwer]

debug.ts is not a valid script?

[holgerd77]

No, not yet. You need to run the client with the new option npm run client:start -- --network=rinkeby --debugCode the final script will then printed out to the console on VM block execution error with the correct values filled in.

[holgerd77]

(so this will work for all future debugging cases)

[jochem-brouwer]

Ah yes, I should have spotted this earlier. You should get the state root of the previous block, and set the state managers' root to the root of that block. (Can probably just get it from vm's blockchain)

[jochem-brouwer]

Should be export DEBUG. If I don't use export then debug is not triggered.

[holgerd77]

Ah, no, export should not be needed. Your are likely putting an && in between the commands?