Truffle: Truffle debug crashes when inspecting memory array

[pertsev]

Issue

Truffle debug crashes when inspecting memory array

Steps to Reproduce

Games.sol

pragma solidity 0.5.4;

contract Games {
    enum GameState { 
        Invalid,
        odd,
        even
    }

    struct Game {
        GameState state;
        bytes32 gameId;
    }

    mapping(bytes32 => Game) public games;

    function recordMany(bytes32[] memory _games) public {
        for (uint i=0; i<_games.length; i++) {
            Game storage game = games[_games[i]];
            game.state = GameState.odd;
        }
    }
}

games.test.js

const Games = artifacts.require("Games")

const {randomHex} = web3.utils

contract('Games', async (accounts) => {
  let gameIds = []
  let gamesInstance

  before(async () => {
    for(i=0; i < 2; i++) {
      gameIds.push(randomHex(32))
    }
    gamesInstance = await Games.deployed()
  })

  describe.only('#recordMany', async () => {
    it('get all games states', async () => {
      await gamesInstance.recordMany(gameIds)
    })
  })
})

1. run tests
2. start debugging of test's tx
3. show local variables (v) at line 19

Expected Behavior

v should show local variables

Actual Results

an exception thrown

TypeError: Cannot read property '10' of undefined
    at Object.storageSize (/usr/local/lib/node_modules/truffle/build/webpack:/packages/truffle-decoder/dist/allocate/storage.js:162:1)
    at storageSizeAndAllocate (/usr/local/lib/node_modules/truffle/build/webpack:/packages/truffle-decoder/dist/allocate/storage.js:245:1)

Environment

• Operating System:
• Ethereum client:
  Truffle v5.0.6 (core: 5.0.6)
  Solidity - 0.5.4 (solc-js)
  Node v11.8.0

---

Bug submitted by peppersec.com

[gnidan]

Thanks for raising this issue! We'll look into it and someone will get back to you.

[haltman-at]

OK, I've created PR #1788 to fix this bug. For what it's worth, the problem is not related to memory arrays; rather it was related to local variables of struct storage type, hence why it occurred on line 19, where the local Game storage game was declared.

(Edit: For what it's worth, a local storage variable that was a statically-sized array of structs would also have triggered the bug.)

[rstormsf]

It was discovered during one of the security audits we have been performing with truffle suite. Thanks again to Truffle team for building amazing tools for auditors.

[gnidan]

Just released Truffle v5.0.7 containing the fix for this. Could you try it out and let us know if it's not fixed? Thanks again!