Hardhat and foundry, contract compile bytecode different

[congtanwkm]

Component

Forge

Have you ensured that all of these are up to date?

• Foundry
• Foundryup

What version of Foundry are you on?

forge 0.2.0 (394f217 2023-03-21T00:11:00.708322Z)

What command(s) is the bug in?

forge test

Operating System

None

Describe the bug

I'm developing contracts on a hardhat project, and I want to write test for it by foundry. The problem I'm facing is: In my contract, I will create a new child contract with the same salt + constructor params, but when running it on foundry and hardhat, it provides different addresses. After looking for the issue, I found that bytecode of child contract from foundry and hardhat is not the same, it means the bytecode which is compiled by foundry (in out) and hardhat (in artifacts) are different. My test in hardhat worked well, I can predict the child contract address by ethers.utils.getCreate2Address in js.

I wonder if there is any difference between the hardhat config and foundry toml, but after many try with many kinds of config, the problem is still there.
Is there any way to ensure that the config of hardhat and foundry execute the same.

This is my smart contract code:

contract Parent {

  function born(bytes32 id, string memory name, uint256 weight) external  returns(address) {
      Child child = new Child{salt: id}(name, weight);
      return address(child);
  }
}

hardhat config:

config = {
  solidity: {
    version: "0.8.18",
    evmVersion: "london",
    settings: {
      optimizer: {
        enabled: true,
        runs: 200,
      },
    },
  }
...
}

foundry config

[profile.default]
src = 'contracts'
out = 'out'
libs = ['node_modules', 'lib']
test = 'test/foundry'
cache_path  = 'forge-cache'
gas_reports = ["*"]
optimizer = true
optimizer_runs = 200
solc = "0.8.18"
evm_version = "london"
auto_detect_solc = false

Forge version: 0.2.0
Hardhat version: 2.14.0

[mattsse]

which is compiled by foundry (in out) and hardhat (in artifacts) are different.

different how? metadata hash?

[congtanwkm]

different how? metadata hash?

You can see the image, both bytecode from hardhat and foundry has the same length, but different ~30 bytes near the end

[congtanwkm]

I tried another simple contract which has shorter bytecode. This is contract code:

pragma solidity 0.8.18;
contract Lock {
    uint256 public unlockTime;
    address payable public owner;
    event Withdrawal(uint256 amount, uint256 when);

    constructor(uint256 _unlockTime) payable {
        require(block.timestamp < _unlockTime, "Unlock time should be in the future");
        unlockTime = _unlockTime;
        owner = payable(msg.sender);
    }
    function withdraw() public {
        require(block.timestamp >= unlockTime, "You can't withdraw yet");
        require(msg.sender == owner, "You aren't the owner");
        emit Withdrawal(address(this).balance, block.timestamp);
        owner.transfer(address(this).balance);
    }
}

Hardhat compiled bytecode:

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

foundry bytecode:

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

Compare:

[mds1]

These are different metadata hashes. The trailing 0033 is the length of the metadata hash (51 btyes) and it starts at the a264 bytes (in the most recent screenshot, second row from the bottom, near the beginning of the row). See the solidity docs for more info.

If that's the only difference the actual executable code is identical and this difference is expected. The metadata hash is a function of various things, including filepaths, so if foundry and hardhat handle e.g. remappings differently you'll get a different hash.

Note that both foundry and hardhat provide options to turns off this bytecode hash if you'd like to remove the discrepancy.

Going to close this since this is solved, but feel free to ask any more questions :)