hardhat-resolc

hardhat-resolc

Plugin for compiling Solidity Smart Contracts to PolkaVM.

NOTE: resolc is compatible with solidity versions higher than 0.8.0.

This plugin allows for seamless transition between EVM and PolkaVM environments, by enabling compilation of Solidity Smart Contracts to PolkaVM compatible hardhat artifacts, in order to facilitate deployment or testing.

Description

This plugin overrides the compile tasks in order to replace compiler from solc to pallet revive's resolc. At the same time it allows for selecting either remix as the compilation backend or the resolc binary, with full support for their respective optional commands.

Requirements

In order to use the plugin, it must be imported at the top of the hardhat.config file, in order to override the relevant hardhat tasks.

When using the resolc binary, it's required to state the path to the binary and fullfiling all other requirements as described by the installation section of the pallet revive repo. If you need to compile to a solidity version different from the solc you have installed, the corresponding version's binary must be present and the path specified in the configuration.

NOTE Usage of absolute paths are recommended.

When using the remix backend for compilation, the solidity version of the project must be >= 0.8.0, since the backend is hardcoded for that compiler version.

Configuration

Please refer to the ResolcConfig type to see the available configuration options, as well as the resolc compiler's --help section for more detailed information on each.

When using the remix backend for compilation, the only available configuration options are within the optimization field, and are enabling or disabling the optimization through the enable option and defining the number of runs for the optimizer under the option with the same name.

When using the resolc binary, the same configuration options as when using the binary on its own are available.

Inside of the hardhat configuration file, you must define both that the VM is polkavm inside the hardhat network and the resolc options, such as the following:

const config: HardhatUserConfig = {
  solidity: "0.8.28",
  networks: {
    hardhat: {
      polkavm: true
    }
  },
  resolc: {
    compilerSource: 'remix',
    settings: {
      optimizer: {
        enabled: true,
        runs: 400
      },
      evmVersion: "istanbul"
    },
  },
};

You must also import the plugin at the top of the configuration file in order to override the compiler.

This configuration will have hardhat interact with the chain as if with a live chain, since the forking capability is not yet integrated. As a workaround, you can fork the Asset Hub mainnet with a tool such as @acala-network/chopsticks and then use the eth-rpc-adapter in order to provide the fork with the required ethereum-compatible calls.

Compatibility

This plugin shares the same compatibility requirements as the resolc compiler, such as:

• Have the solc binary installed.
• Have a build of LLVM 18.1.4 or later including compiler-rt

Regarding hardhat compatibility, even though it's set as part of the hardhat type in the NetworksConfig type, it is not compatible with hardhat-only helpers, such as time and loadFixture from @nomicfoundation/hardhat-toolbox/network-helpers, due to the node missing some rpc calls necessary for these calls to work.

When running against a local node, or against a fork of the live chain, you must make sure that the binaries employed are compatible with eachother. In order to do this, you can check inside pallet revive's Cargo.toml in order to see which commit of the polkadot-sdk you should use to build the substrate-node and eth-rpc-adapter binaries. If there is a missmatch betwween these versions, deployment will fail with CodeRejected or Metadata error: The generated code is not compatible with the node.