feat(cast) add creation-code method [#8973] (#9029)

* feat(cast) add creation-code method [#8973]

* Fix typo

* Fix CI

* Code review fixes

* Add creation-code flags and creation-args

* Update comments

* eyre style fixes

* typo

* use r#".."# for snapbox

* Apply suggestions from code review

* fix test regression

* tag arguments as mutually exclusive

* use unreachable!

* Rename and add abi_path param

* Decode constructor args

* Update crates/cast/bin/cmd/constructor_args.rs

* fix test

* Update crates/cast/bin/args.rs

Co-authored-by: zerosnacks <95942363+zerosnacks@users.noreply.github.com>

* Update crates/cast/bin/cmd/creation_code.rs

Co-authored-by: zerosnacks <95942363+zerosnacks@users.noreply.github.com>

* Update crates/cast/bin/cmd/creation_code.rs

Co-authored-by: zerosnacks <95942363+zerosnacks@users.noreply.github.com>

* Fix formatting

* Code review fixes

---------

Co-authored-by: zerosnacks <zerosnacks@protonmail.com>
Co-authored-by: zerosnacks <95942363+zerosnacks@users.noreply.github.com>

crates/cast/Cargo.toml

@@ -44,9 +44,14 @@ alloy-json-abi.workspace = true
 alloy-json-rpc.workspace = true
 alloy-network.workspace = true
 alloy-primitives.workspace = true
-alloy-provider = { workspace = true, features = ["reqwest", "ws", "ipc"] }
+alloy-provider = { workspace = true, features = [
+    "reqwest",
+    "ws",
+    "ipc",
+    "trace-api",
+] }
 alloy-rlp.workspace = true
-alloy-rpc-types = { workspace = true, features = ["eth"] }
+alloy-rpc-types = { workspace = true, features = ["eth", "trace"] }
 alloy-serde.workspace = true
 alloy-signer-local = { workspace = true, features = ["mnemonic", "keystore"] }
 alloy-signer.workspace = true

crates/cast/bin/args.rs

@@ -1,5 +1,6 @@
 use crate::cmd::{
-    access_list::AccessListArgs, bind::BindArgs, call::CallArgs, create2::Create2Args,
+    access_list::AccessListArgs, bind::BindArgs, call::CallArgs,
+    constructor_args::ConstructorArgsArgs, create2::Create2Args, creation_code::CreationCodeArgs,
     estimate::EstimateArgs, find_block::FindBlockArgs, interface::InterfaceArgs, logs::LogsArgs,
     mktx::MakeTxArgs, rpc::RpcArgs, run::RunArgs, send::SendTxArgs, storage::StorageArgs,
     wallet::WalletSubcommands,
@@ -937,6 +938,14 @@ pub enum CastSubcommand {
         command: WalletSubcommands,
     },
 
+    /// Download a contract creation code from Etherscan and RPC.
+    #[command(visible_alias = "cc")]
+    CreationCode(CreationCodeArgs),
+
+    /// Display constructor arguments used for the contract initialization.
+    #[command(visible_alias = "cra")]
+    ConstructorArgs(ConstructorArgsArgs),
+
     /// Generate a Solidity interface from a given ABI.
     ///
     /// Currently does not support ABI encoder v2.

crates/cast/bin/cmd/constructor_args.rs

@@ -0,0 +1,100 @@
+use alloy_dyn_abi::DynSolType;
+use alloy_primitives::{Address, Bytes};
+use clap::{command, Parser};
+use eyre::{eyre, OptionExt, Result};
+use foundry_block_explorers::Client;
+use foundry_cli::{
+    opts::{EtherscanOpts, RpcOpts},
+    utils,
+};
+use foundry_config::Config;
+
+use super::{
+    creation_code::fetch_creation_code,
+    interface::{fetch_abi_from_etherscan, load_abi_from_file},
+};
+
+/// CLI arguments for `cast creation-args`.
+#[derive(Parser)]
+pub struct ConstructorArgsArgs {
+    /// An Ethereum address, for which the bytecode will be fetched.
+    contract: Address,
+
+    /// Path to file containing the contract's JSON ABI. It's necessary if the target contract is
+    /// not verified on Etherscan
+    #[arg(long)]
+    abi_path: Option<String>,
+
+    #[command(flatten)]
+    etherscan: EtherscanOpts,
+
+    #[command(flatten)]
+    rpc: RpcOpts,
+}
+
+impl ConstructorArgsArgs {
+    pub async fn run(self) -> Result<()> {
+        let Self { contract, etherscan, rpc, abi_path } = self;
+
+        let config = Config::from(&etherscan);
+        let chain = config.chain.unwrap_or_default();
+        let api_key = config.get_etherscan_api_key(Some(chain)).unwrap_or_default();
+        let client = Client::new(chain, api_key)?;
+
+        let config = Config::from(&rpc);
+        let provider = utils::get_provider(&config)?;
+
+        let bytecode = fetch_creation_code(contract, client, provider).await?;
+
+        let args_arr = parse_constructor_args(bytecode, contract, &etherscan, abi_path).await?;
+        for arg in args_arr {
+            let _ = sh_println!("{arg}");
+        }
+
+        Ok(())
+    }
+}
+
+/// Fetches the constructor arguments values and types from the creation bytecode and ABI.
+async fn parse_constructor_args(
+    bytecode: Bytes,
+    contract: Address,
+    etherscan: &EtherscanOpts,
+    abi_path: Option<String>,
+) -> Result<Vec<String>> {
+    let abi = if let Some(abi_path) = abi_path {
+        load_abi_from_file(&abi_path, None)?
+    } else {
+        fetch_abi_from_etherscan(contract, etherscan).await?
+    };
+
+    let abi = abi.into_iter().next().ok_or_eyre("No ABI found.")?;
+    let (abi, _) = abi;
+
+    let constructor = abi.constructor.ok_or_else(|| eyre!("No constructor found."))?;
+
+    if constructor.inputs.is_empty() {
+        return Err(eyre!("No constructor arguments found."));
+    }
+
+    let args_size = constructor.inputs.len() * 32;
+    let args_bytes = Bytes::from(bytecode[bytecode.len() - args_size..].to_vec());
+
+    let display_args: Vec<String> = args_bytes
+        .chunks(32)
+        .enumerate()
+        .map(|(i, arg)| {
+            format_arg(&constructor.inputs[i].ty, arg).expect("Failed to format argument.")
+        })
+        .collect();
+
+    Ok(display_args)
+}
+
+fn format_arg(ty: &str, arg: &[u8]) -> Result<String> {
+    let arg_type: DynSolType = ty.parse().expect("Invalid ABI type.");
+    let decoded = arg_type.abi_decode(arg)?;
+    let bytes = Bytes::from(arg.to_vec());
+
+    Ok(format!("{bytes} → {decoded:?}"))
+}

crates/cast/bin/cmd/creation_code.rs

@@ -0,0 +1,167 @@
+use alloy_primitives::{Address, Bytes};
+use alloy_provider::{ext::TraceApi, Provider};
+use alloy_rpc_types::trace::parity::{Action, CreateAction, CreateOutput, TraceOutput};
+use cast::SimpleCast;
+use clap::{command, Parser};
+use eyre::{eyre, OptionExt, Result};
+use foundry_block_explorers::Client;
+use foundry_cli::{
+    opts::{EtherscanOpts, RpcOpts},
+    utils,
+};
+use foundry_common::provider::RetryProvider;
+use foundry_config::Config;
+
+use super::interface::{fetch_abi_from_etherscan, load_abi_from_file};
+
+/// CLI arguments for `cast creation-code`.
+#[derive(Parser)]
+pub struct CreationCodeArgs {
+    /// An Ethereum address, for which the bytecode will be fetched.
+    contract: Address,
+
+    /// Path to file containing the contract's JSON ABI. It's necessary if the target contract is
+    /// not verified on Etherscan.
+    #[arg(long)]
+    abi_path: Option<String>,
+
+    /// Disassemble bytecodes into individual opcodes.
+    #[arg(long)]
+    disassemble: bool,
+
+    /// Return creation bytecode without constructor arguments appended.
+    #[arg(long, conflicts_with = "only_args")]
+    without_args: bool,
+
+    /// Return only constructor arguments.
+    #[arg(long)]
+    only_args: bool,
+
+    #[command(flatten)]
+    etherscan: EtherscanOpts,
+
+    #[command(flatten)]
+    rpc: RpcOpts,
+}
+
+impl CreationCodeArgs {
+    pub async fn run(self) -> Result<()> {
+        let Self { contract, etherscan, rpc, disassemble, without_args, only_args, abi_path } =
+            self;
+
+        let config = Config::from(&etherscan);
+        let chain = config.chain.unwrap_or_default();
+        let api_key = config.get_etherscan_api_key(Some(chain)).unwrap_or_default();
+        let client = Client::new(chain, api_key)?;
+
+        let config = Config::from(&rpc);
+        let provider = utils::get_provider(&config)?;
+
+        let bytecode = fetch_creation_code(contract, client, provider).await?;
+
+        let bytecode =
+            parse_code_output(bytecode, contract, &etherscan, abi_path, without_args, only_args)
+                .await?;
+
+        if disassemble {
+            let _ = sh_println!("{}", SimpleCast::disassemble(&bytecode)?);
+        } else {
+            let _ = sh_println!("{bytecode}");
+        }
+
+        Ok(())
+    }
+}
+
+/// Parses the creation bytecode and returns one of the following:
+/// - The complete bytecode
+/// - The bytecode without constructor arguments
+/// - Only the constructor arguments
+async fn parse_code_output(
+    bytecode: Bytes,
+    contract: Address,
+    etherscan: &EtherscanOpts,
+    abi_path: Option<String>,
+    without_args: bool,
+    only_args: bool,
+) -> Result<Bytes> {
+    if !without_args && !only_args {
+        return Ok(bytecode);
+    }
+
+    let abi = if let Some(abi_path) = abi_path {
+        load_abi_from_file(&abi_path, None)?
+    } else {
+        fetch_abi_from_etherscan(contract, etherscan).await?
+    };
+
+    let abi = abi.into_iter().next().ok_or_eyre("No ABI found.")?;
+    let (abi, _) = abi;
+
+    if abi.constructor.is_none() {
+        if only_args {
+            return Err(eyre!("No constructor found."));
+        }
+        return Ok(bytecode);
+    }
+
+    let constructor = abi.constructor.unwrap();
+    if constructor.inputs.is_empty() {
+        if only_args {
+            return Err(eyre!("No constructor arguments found."));
+        }
+        return Ok(bytecode);
+    }
+
+    let args_size = constructor.inputs.len() * 32;
+
+    let bytecode = if without_args {
+        Bytes::from(bytecode[..bytecode.len() - args_size].to_vec())
+    } else if only_args {
+        Bytes::from(bytecode[bytecode.len() - args_size..].to_vec())
+    } else {
+        unreachable!();
+    };
+
+    Ok(bytecode)
+}
+
+/// Fetches the creation code of a contract from Etherscan and RPC.
+pub async fn fetch_creation_code(
+    contract: Address,
+    client: Client,
+    provider: RetryProvider,
+) -> Result<Bytes> {
+    let creation_data = client.contract_creation_data(contract).await?;
+    let creation_tx_hash = creation_data.transaction_hash;
+    let tx_data = provider.get_transaction_by_hash(creation_tx_hash).await?;
+    let tx_data = tx_data.ok_or_eyre("Could not find creation tx data.")?;
+
+    let bytecode = if tx_data.inner.to.is_none() {
+        // Contract was created using a standard transaction
+        tx_data.inner.input
+    } else {
+        // Contract was created using a factory pattern or create2
+        // Extract creation code from tx traces
+        let mut creation_bytecode = None;
+
+        let traces = provider.trace_transaction(creation_tx_hash).await.map_err(|e| {
+            eyre!("Could not fetch traces for transaction {}: {}", creation_tx_hash, e)
+        })?;
+
+        for trace in traces {
+            if let Some(TraceOutput::Create(CreateOutput { address, .. })) = trace.trace.result {
+                if address == contract {
+                    creation_bytecode = match trace.trace.action {
+                        Action::Create(CreateAction { init, .. }) => Some(init),
+                        _ => None,
+                    };
+                }
+            }
+        }
+
+        creation_bytecode.ok_or_else(|| eyre!("Could not find contract creation trace."))?
+    };
+
+    Ok(bytecode)
+}

crates/cast/bin/cmd/interface.rs

@@ -108,7 +108,7 @@ struct InterfaceSource {
 }
 
 /// Load the ABI from a file.
-fn load_abi_from_file(path: &str, name: Option<String>) -> Result<Vec<(JsonAbi, String)>> {
+pub fn load_abi_from_file(path: &str, name: Option<String>) -> Result<Vec<(JsonAbi, String)>> {
     let file = std::fs::read_to_string(path).wrap_err("unable to read abi file")?;
     let obj: ContractObject = serde_json::from_str(&file)?;
     let abi = obj.abi.ok_or_else(|| eyre::eyre!("could not find ABI in file {path}"))?;
@@ -139,7 +139,7 @@ fn load_abi_from_artifact(path_or_contract: &str) -> Result<Vec<(JsonAbi, String
 }
 
 /// Fetches the ABI of a contract from Etherscan.
-async fn fetch_abi_from_etherscan(
+pub async fn fetch_abi_from_etherscan(
     address: Address,
     etherscan: &EtherscanOpts,
 ) -> Result<Vec<(JsonAbi, String)>> {

crates/cast/bin/cmd/mod.rs

@@ -8,7 +8,9 @@
 pub mod access_list;
 pub mod bind;
 pub mod call;
+pub mod constructor_args;
 pub mod create2;
+pub mod creation_code;
 pub mod estimate;
 pub mod find_block;
 pub mod interface;

crates/cast/bin/main.rs

@@ -206,6 +206,8 @@ async fn main_args(args: CastArgs) -> Result<()> {
             sh_println!("{}", SimpleCast::calldata_encode(sig, &args)?)?;
         }
         CastSubcommand::Interface(cmd) => cmd.run().await?,
+        CastSubcommand::CreationCode(cmd) => cmd.run().await?,
+        CastSubcommand::ConstructorArgs(cmd) => cmd.run().await?,
         CastSubcommand::Bind(cmd) => cmd.run().await?,
         CastSubcommand::PrettyCalldata { calldata, offline } => {
             let calldata = stdin::unwrap_line(calldata)?;