feat(executor): transaction builder + eth_call simulator#41
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New `charon-executor` crate. Two modules — both deliberately small, both passive (no broadcast / no signing of arbitrary inputs / no state held beyond config). Pipeline glue (#15) wires them together. builder.rs — `TxBuilder`: - `encode_calldata(opp, params)` — packs the protocol-specific `LiquidationParams::Venus` plus underlying-token addresses from the `LiquidationOpportunity` into the on-chain `CharonLiquidationParams` struct (lockstep with the Solidity source) and ABI-encodes the outer `executeLiquidation(...)` call via `alloy::sol!` + `SolCall::abi_encode` - `build_tx(provider, calldata, max_fee, priority_fee, gas_limit)` — assembles an EIP-1559 `TransactionRequest`, fetching the latest nonce for the bot signer - `sign(tx)` — signs via `EthereumWallet`, returns raw EIP-2718 envelope bytes ready for `eth_sendRawTransaction` or a Flashbots bundle. **Does not broadcast.** - Test pins selector against `executeLiquidationCall::SELECTOR` (catches accidental drift between Rust + Solidity struct shapes) simulation.rs — `Simulator`: - `simulate(provider, calldata)` — `eth_call` against latest block. Ok = caller may broadcast; Err = revert reason logged at WARN, caller drops the opportunity. Zero gas spent. Constants pinned: `PROTOCOL_VENUS = 3` matches the Solidity constant. `CharonLiquidationParams` field order/types must match `contracts/src/CharonLiquidator.sol` exactly — the selector test will fail if either side drifts.
This was referenced Apr 23, 2026
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[executor] charon-executor still missing from workspace members — fourth consecutive PR flagged
#199
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…able the swap leg hard-coded `fee: 3000` (0.30 %). that tier does not exist or has near-zero liquidity for several Venus-collateral pairs on PCS V3: BTCB/USDT sits in the 0.05 % (500) pool, ETH/USDT in the 0.01 % (100) pool, XVS/WBNB in the 1 % (10000) pool. routing those through the 0.30 % pool would revert on `SPL` or eat unbounded slippage. add `uint24 swapPoolFee` to LiquidationParams, validate non-zero in executeLiquidation, and pass it to ExactInputSingleParams.fee. the off-chain opportunity router now selects the deepest pool per pair. abi layout note: this extends LiquidationParams with a new tail field. the companion Rust `LiquidationParams` builder in the charon-executor crate (not yet present on this branch — lands with PR #41) must mirror the added field. closes #122
- Redact PrivateKeySigner in TxBuilder Debug to avoid leaking the k256 scalar into logs (#158). - Pull nonce from the pending block tag so queued tx don't collide with newly built ones; TODO flags NonceManager in PR #43 (#159). - Reject build_tx calls where priority tip exceeds max fee per gas before any RPC round-trip (#160). - Require an explicit gas_limit on Simulator::simulate so the simulation burns the same gas ceiling as the real broadcast (#161). - Add Simulator::from_builder so the simulated sender is always the builder's hot wallet (onlyOwner alignment), plus debug_assert on non-zero sender (#162). - Replace anyhow on the public lib surface with BuilderError and SimulationError thiserror enums (#163). - Pin PROTOCOL_VENUS to the Solidity constant with an ABI-level unit test and line-number comment referencing CharonLiquidator.sol:49 (#164). - Adopt workspace lints (unsafe_code=forbid, arithmetic_side_effects, cast_possible_truncation, unwrap_used) and opt charon-executor in via [lints] workspace = true (#165). - Decode revert payload in Simulator::simulate into a 4-byte selector plus full hex body so logs are greppable cross-protocol (#166). - Add #[ignore]d fork tests covering the happy path and the onlyOwner adversarial path to pin the sim gate's safety invariant (#167). Closes #158 Closes #159 Closes #160 Closes #161 Closes #162 Closes #163 Closes #164 Closes #165 Closes #166 Closes #167
…der-and-sim # Conflicts: # Cargo.toml
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Closes #15
New
charon-executorcrate. Two modules, both small and passive (no broadcast, no signing of arbitrary inputs, no state held beyond config). Pipeline glue wires them together in a later PR.builder.rs—TxBuilder:encode_calldata(opp, params)— packsLiquidationParams::Venus+ underlying-token addresses from the opportunity into the on-chainCharonLiquidationParamsstruct (lockstep with Solidity) and ABI-encodes the outerexecuteLiquidation(...)call viaalloy::sol!+SolCall::abi_encodebuild_tx(provider, calldata, max_fee, priority_fee, gas_limit)— assembles EIP-1559TransactionRequest, fetches the latest nonce for the bot signersign(tx)— signs viaEthereumWallet, returns raw EIP-2718 envelope bytes. Does not broadcast.executeLiquidationCall::SELECTOR(catches accidental drift between Rust + Solidity struct shapes)simulation.rs—Simulator:simulate(provider, calldata)—eth_callagainst latest block.Ok= caller may broadcast;Err= revert reason logged at WARN, caller drops the opportunity. Zero gas spent.Constants pinned:
PROTOCOL_VENUS = 3matches Solidity constant.CharonLiquidationParamsfield order/types must matchcontracts/src/CharonLiquidator.solexactly — selector test fails if either side drifts.Depends on
feat/15-profit-calc-and-queue.