Contract Factories

Contract factories are now supported by Warp. Contract factories work slightly differently on Starknet as they do on Ethereum. To deploy a contract on Starknet we need to know the class hash of the contract being deployed, this class hash is then passed as an argument to the deploy system call. Warp is designed so that the above is hidden from the user and handled internally. The class hash is calculated offline and inserted into the transpiled Contract factory as a constant.

Note that the contract being deployed by the contract factory will still need to be declared online by the user.

⚠️ Warning: Warp also supports the use of the salt option i.e new Contract{salt: salt}() but because of core differences between Ethereum and Starknet the salt value will be truncated from 32 to the 31 most significant bytes.

The following Solidity contract named example.sol will be used to illustrate the feature:

pragma solidity ^0.8.14;

contract DeployedContract {
    uint8 input1;
    uint8 input2;
    constructor(uint8 input1_, uint8 input2_) {
        input1 = input1_;
        input2 = input2_;
    }
}

contract ContractFactory {
    address public deployedContract;

    function deploy() external {
        deployedContract =  address(new DeployedContract(1, 2));
    }
}

Transpile the contract:

warp transpile example.sol --compile-cairo

If we inspect the transpiled ContractFactory file we can see that the class hash of the DeployedContract is inserted as a constant into the file:

# @declare example__WC__DeployedContract.cairo
const _example_DeployedContract_4de2fe6576a500b8 = 0x2a1fa671ab8a9a09bda9147fd7978a1204667a74e9862257b4df5e0b3039f3b

Compare this to the class hash produced by manually declaring the DeployedContract file and you will see they are identical:

warp declare warp_output/example__WC__DeployedContract.cairo
Running starknet compile with cairoPath /home/user/.config/yarn/global/node_modules/@nethermindeth/warp
Declare transaction was sent.
Contract class hash: 0x2a1fa671ab8a9a09bda9147fd7978a1204667a74e9862257b4df5e0b3039f3b
Transaction hash: 0x361de621248d89435c5a4c0624a3ad842784feb2a71ef8d5833b50fb1727610

Now that the DeployedContract has been declared we can move to the next step of deploying an instance of the contract from the ContractFactory contract.

First we need to deploy the ContractFactory:

warp deploy warp_output/example__WC__ContractFactory.cairo
Running starknet compile with cairoPath /home/user/.config/yarn/global/node_modules/@nethermindeth/warp
Running starknet compile with cairoPath /home/user/.config/yarn/global/node_modules/@nethermindeth/warp
Declare transaction was sent.
Contract class hash: 0x5f6d13c91710a9f38b53461b6d7ef67e4fc22ae0c071b1525a10023a4cfcddb
Transaction hash: 0x6137adc00ab3971cab712f042632ffbd126d8ed86debc8ac46da668e64de333

Sending the transaction with max_fee: 0.000001 ETH.
Invoke transaction for contract deployment was sent.
Contract address: 0x050dd6362c74c88530a9f78b756cceb562d25475c6dc612488c52ae881235537
Transaction hash: 0x1e55b1136b0c9735a51f2f778bb46e90058f9df6bc2ed32c94e432c3a82f5c5

Note you can check the transaction status with:

warp status 0x1e55b1136b0c9735a51f2f778bb46e90058f9df6bc2ed32c94e432c3a82f5c5

The status of the transaction will be returned:

{
    "block_hash": "0x1755978ce7c28b71766fa3348a9639e9f166a4afe30ad617be7608ea302a890",
    "tx_status": "ACCEPTED_ON_L2"
}

Now that the ContractFactory has been accepted on L2 we can invoke the deploy command.

warp invoke warp_output/example__WC__ContractFactory.cairo --function deploy --address 0x050dd6362c74c88530a9f78b756cceb562d25475c6dc612488c52ae881235537

Lastly, once the transaction is completed we can call the ContractFactory and get the address of the deployed contract.

warp call warp_output/example__WC__ContractFactory.cairo --function deployedContract --address 0x050dd6362c74c88530a9f78b756cceb562d25475c6dc612488c52ae881235537
Running starknet compile with cairoPath /home/user/.config/yarn/global/node_modules/@nethermindeth/warp
0x74ef3df5514c3aa7320063a699a4d3959dccaf8f1db2b6bd81df7e67dace247