feat(withdrawer): bridged ERC20 token withdrawals (#1149)

## Summary
implement withdrawals of ERC20 tokens that are of type
`AstriaBridgeableERC20` (see implemented contract).

## Background
we want to be able to withdraw ERC20 tokens that are bridged to a
rollup.

## Changes
- implement `AstriaBridgeableERC20` which is a standard `ERC20` contract
with additional functionality for minting (not used by the withdrawer,
implemented/tested here
astriaorg/astria-geth#20) as well as
functionality for withdrawing
- implement `IAstriaWithdrawer` which is implemented by both
`AstriaWithdrawer` and `AstriaMintableERC20`.
- the withdrawer now interacts with a `IAstriaWithdrawer`. both native
assets and ERC20 withdrawals have the same event signatures, so no
additional code was needed for the withdrawer itself.
- to use the withdrawer with an `AstriaBridgeableERC20`, the
`ASTRIA_BRIDGE_WITHDRAWER_ETHEREUM_CONTRACT_ADDRESS` is set to some
`AstriaMintableERC20`, and
`ASTRIA_BRIDGE_WITHDRAWER_ROLLUP_ASSET_DENOMINATION` is set to the
rollup asset's denomination as represented on the sequencer. for
example, if the asset is represented on the sequencer is
`transfer/channel-1/usdc`, that is the rollup asset denomination. the
`name/symbol` of the ERC20 contract are not relevant.
- also update the build script to write the generated abigen contract
bindings to files, this is easier for debugging and unit testing.

## Testing
unit tests

## Related Issues

closes #924

.gitattributes

@@ -1,2 +1,4 @@
 crates/astria-core/src/generated/** linguist-generated=true
+crates/astria-bridge-withdrawer/src/withdrawer/ethereum/generated/** linguist-generated=true
+crates/astria-bridge-withdrawer/ethereum/out/** linguist-generated=true
 specs/** linguist-documentation=true

.github/workflows/test.yml

@@ -133,18 +133,11 @@ jobs:
         with:
           version: "24.4"
           repo-token: ${{ secrets.GITHUB_TOKEN }}
-      - name: Install python and solc
-        uses: actions/setup-python@v5
-        with:
-          python-version: '3.10' 
       - name: Install Foundry
         uses: foundry-rs/foundry-toolchain@v1
       - name: Run tests
         timeout-minutes: 20
         run: |
-          pip install solc-select 
-          solc-select install 0.8.21
-          solc-select use 0.8.21
           cargo nextest run --package astria-bridge-withdrawer -- --include-ignored
 
   doctest:

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "crates/astria-bridge-withdrawer/ethereum/lib/forge-std"]
 	path = crates/astria-bridge-withdrawer/ethereum/lib/forge-std
 	url = https://github.com/foundry-rs/forge-std
+[submodule "crates/astria-bridge-withdrawer/ethereum/lib/openzeppelin-contracts"]
+	path = crates/astria-bridge-withdrawer/ethereum/lib/openzeppelin-contracts
+	url = https://github.com/OpenZeppelin/openzeppelin-contracts

crates/astria-bridge-withdrawer/Cargo.toml

@@ -57,3 +57,4 @@ wiremock = { workspace = true }
 
 [build-dependencies]
 astria-build-info = { path = "../astria-build-info", features = ["build"] }
+ethers = { workspace = true }

crates/astria-bridge-withdrawer/build.rs

@@ -1,4 +1,32 @@
+use ethers::contract::Abigen;
+
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     astria_build_info::emit("bridge-withdrawer-v")?;
+
+    println!("cargo:rerun-if-changed=ethereum/src/AstriaWithdrawer.sol");
+    println!("cargo:rerun-if-changed=ethereum/src/IAstriaWithdrawer.sol");
+    println!("cargo:rerun-if-changed=ethereum/src/AstriaBridgeableERC20.sol");
+
+    Abigen::new(
+        "IAstriaWithdrawer",
+        "./ethereum/out/IAstriaWithdrawer.sol/IAstriaWithdrawer.json",
+    )?
+    .generate()?
+    .write_to_file("./src/withdrawer/ethereum/generated/astria_withdrawer_interface.rs")?;
+
+    Abigen::new(
+        "AstriaWithdrawer",
+        "./ethereum/out/AstriaWithdrawer.sol/AstriaWithdrawer.json",
+    )?
+    .generate()?
+    .write_to_file("./src/withdrawer/ethereum/generated/astria_withdrawer.rs")?;
+
+    Abigen::new(
+        "AstriaBridgeableERC20",
+        "./ethereum/out/AstriaBridgeableERC20.sol/AstriaBridgeableERC20.json",
+    )?
+    .generate()?
+    .write_to_file("./src/withdrawer/ethereum/generated/astria_bridgeable_erc20.rs")?;
+
     Ok(())
 }

crates/astria-bridge-withdrawer/ethereum/src/AstriaBridgeableERC20.sol

@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: MIT or Apache-2.0
+pragma solidity ^0.8.21;
+
+import {IAstriaWithdrawer} from "./IAstriaWithdrawer.sol";
+import {ERC20} from "lib/openzeppelin-contracts/contracts/token/ERC20/ERC20.sol";
+
+contract AstriaBridgeableERC20 is IAstriaWithdrawer, ERC20 {
+    // the `astriaBridgeSenderAddress` built into the astria-geth node
+    address public immutable BRIDGE;
+
+    // the divisor used to convert the rollup asset amount to the base chain denomination
+    //
+    // set to 10 ** (TOKEN_DECIMALS - BASE_CHAIN_ASSET_PRECISION) on contract creation
+    uint256 private immutable DIVISOR;
+
+    // emitted when tokens are minted from a deposit
+    event Mint(address indexed account, uint256 amount);
+
+    modifier onlyBridge() {
+        require(msg.sender == BRIDGE, "AstriaBridgeableERC20: only bridge can mint");
+        _;
+    }
+
+    constructor(
+        address _bridge,
+        uint32 _baseChainAssetPrecision,
+        string memory _name,
+        string memory _symbol
+    ) ERC20(_name, _symbol) {
+        uint8 decimals = decimals();
+        if (_baseChainAssetPrecision > decimals) {
+            revert("AstriaBridgeableERC20: base chain asset precision must be less than or equal to token decimals");
+        }
+
+        BASE_CHAIN_ASSET_PRECISION = _baseChainAssetPrecision;
+        DIVISOR = 10 ** (decimals - _baseChainAssetPrecision);
+        BRIDGE = _bridge;
+    }
+
+    modifier sufficientValue(uint256 amount) {
+        require(amount / DIVISOR > 0, "AstriaBridgeableERC20: insufficient value, must be greater than 10 ** (TOKEN_DECIMALS - BASE_CHAIN_ASSET_PRECISION)");
+        _;
+    }
+
+    function mint(address _to, uint256 _amount)
+        external
+        onlyBridge
+    {
+        _mint(_to, _amount);
+        emit Mint(_to, _amount);
+    }
+
+    function withdrawToSequencer(uint256 _amount, address _destinationChainAddress)
+        external
+        sufficientValue(_amount)
+    {
+        _burn(msg.sender, _amount);
+        emit SequencerWithdrawal(msg.sender, _amount, _destinationChainAddress);
+    }
+
+    function withdrawToIbcChain(uint256 _amount, string calldata _destinationChainAddress, string calldata _memo)
+        external
+        sufficientValue(_amount)
+    {
+        _burn(msg.sender, _amount);
+        emit Ics20Withdrawal(msg.sender, _amount, _destinationChainAddress, _memo);
+    }
+}

crates/astria-bridge-withdrawer/ethereum/src/AstriaWithdrawer.sol

@@ -1,20 +1,15 @@
 // SPDX-License-Identifier: MIT or Apache-2.0
 pragma solidity ^0.8.21;
 
+import {IAstriaWithdrawer} from "./IAstriaWithdrawer.sol";
+
 // This contract facilitates withdrawals of the native asset from the rollup to the base chain.
 // 
 // Funds can be withdrawn to either the sequencer or the origin chain via IBC.
-contract AstriaWithdrawer {
-    // the precision of the asset on the base chain.
-    //
-    // the amount transferred on the base chain will be divided by 10 ^ (18 - BASE_CHAIN_ASSET_PRECISION).
-    //
-    // for example, if base chain asset is precision is 6, the divisor would be 10^12.
-    uint32 public immutable BASE_CHAIN_ASSET_PRECISION;
-
+contract AstriaWithdrawer is IAstriaWithdrawer {
     // the divisor used to convert the rollup asset amount to the base chain denomination
     //
-    // set to 10^ASSET_WITHDRAWAL_DECIMALS on contract creation
+    // set to 10 ** (18 - BASE_CHAIN_ASSET_PRECISION) on contract creation
     uint256 private immutable DIVISOR;
 
     constructor(uint32 _baseChainAssetPrecision) {
@@ -25,20 +20,6 @@ contract AstriaWithdrawer {
         DIVISOR = 10 ** (18 - _baseChainAssetPrecision);
     }
 
-    // emitted when a withdrawal to the sequencer is initiated
-    //
-    // the `sender` is the evm address that initiated the withdrawal
-    // the `destinationChainAddress` is the address on the sequencer the funds will be sent to
-    event SequencerWithdrawal(address indexed sender, uint256 indexed amount, address destinationChainAddress);
-
-    // emitted when a withdrawal to the origin chain is initiated.
-    // the withdrawal is sent to the origin chain via IBC from the sequencer using the denomination trace.
-    //
-    // the `sender` is the evm address that initiated the withdrawal
-    // the `destinationChainAddress` is the address on the origin chain the funds will be sent to
-    // the `memo` is an optional field that will be used as the ICS20 packet memo
-    event Ics20Withdrawal(address indexed sender, uint256 indexed amount, string destinationChainAddress, string memo);
-
     modifier sufficientValue(uint256 amount) {
         require(amount / DIVISOR > 0, "AstriaWithdrawer: insufficient value, must be greater than 10 ** (18 - BASE_CHAIN_ASSET_PRECISION)");
         _;

crates/astria-bridge-withdrawer/ethereum/src/IAstriaWithdrawer.sol

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: MIT or Apache-2.0
+pragma solidity ^0.8.21;
+
+abstract contract IAstriaWithdrawer {
+    // the precision of the asset on the base chain.
+    //
+    // the amount transferred on the base chain will be divided by 10 ^ (18 - BASE_CHAIN_ASSET_PRECISION).
+    //
+    // for example, if base chain asset is precision is 6, the divisor would be 10^12.
+    uint32 public immutable BASE_CHAIN_ASSET_PRECISION;
+
+    // emitted when a withdrawal to the sequencer is initiated
+    //
+    // the `sender` is the evm address that initiated the withdrawal
+    // the `destinationChainAddress` is the address on the sequencer the funds will be sent to
+    event SequencerWithdrawal(address indexed sender, uint256 indexed amount, address destinationChainAddress);
+
+    // emitted when a withdrawal to the IBC origin chain is initiated.
+    // the withdrawal is sent to the origin chain via IBC from the sequencer using the denomination trace.
+    //
+    // the `sender` is the evm address that initiated the withdrawal
+    // the `destinationChainAddress` is the address on the origin chain the funds will be sent to
+    // the `memo` is an optional field that will be used as the ICS20 packet memo
+    event Ics20Withdrawal(address indexed sender, uint256 indexed amount, string destinationChainAddress, string memo);
+}

crates/astria-bridge-withdrawer/src/withdrawer/ethereum/convert.rs

@@ -28,7 +28,7 @@ use serde::{
     Serialize,
 };
 
-use crate::withdrawer::ethereum::astria_withdrawer::{
+use crate::withdrawer::ethereum::astria_withdrawer_interface::{
     Ics20WithdrawalFilter,
     SequencerWithdrawalFilter,
 };
@@ -182,7 +182,7 @@ fn calculate_packet_timeout_time(timeout_delta: Duration) -> eyre::Result<u64> {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::withdrawer::ethereum::astria_withdrawer::SequencerWithdrawalFilter;
+    use crate::withdrawer::ethereum::astria_withdrawer_interface::SequencerWithdrawalFilter;
 
     #[test]
     fn event_to_bridge_unlock() {