Surface transfer simulation revert reasons in order creation API

[squadgazzz]

Summary

• When order creation fails with TransferSimulationFailed, the API now includes the actual revert reason (e.g. 0x5b263df7 = LtvValidationFailed()) instead of the generic "sell token cannot be transferred"
• Changed Balances.sol helper contract to capture revert bytes from the transferFromAccounts try/catch block
• Threaded revert bytes through Simulation → TransferSimulationError::TransferFailed(Vec<u8>) → ValidationError::TransferSimulationFailed(Vec<u8>) → API error description
• Deployed new Balances contract at 0x88b4B74082BffB2976C306CB3f7E9093AE48B94F on all chains (except Lens which keeps the old deployment)
• Updated e2e forked test block numbers to include the new deployment

Motivation

Aave aTokens (e.g. aBasUSDC) revert with LtvValidationFailed() when a user has zero-LTV collateral blocking transfers. The current generic error gives no indication of why the transfer fails, making it very difficult to debug.

API Change

Before:

{"errorType": "TransferSimulationFailed", "description": "sell token cannot be transferred"}

After (when revert data available):

{"errorType": "TransferSimulationFailed", "description": "sell token cannot be transferred, token reverted with: 0x5b263df7"}

The 4-byte selector can be decoded client-side (e.g. cast 4byte 0x5b263df7 → LtvValidationFailed()).

Changes

• contracts/solidity/Balances.sol — catch → catch (bytes memory reason), added transferRevertReason return value
• contracts/artifacts/Balances.json — Rebuilt with solc
• crates/account-balances/src/lib.rs — Added transfer_revert_reason to Simulation, changed TransferFailed to carry Vec<u8>, switched to abi_decode_params (required for dynamic return types)
• crates/account-balances/src/simulation.rs — Pass revert bytes into TransferFailed
• crates/shared/src/order_validation.rs — Thread Vec<u8> through TransferSimulationFailed
• crates/orderbook/src/api/post_order.rs — Format revert selector in error description
• contracts/src/main.rs — Updated Balances addresses to new deployment 0x88b4B74082BffB2976C306CB3f7E9093AE48B94F
• Justfile — Added formatting steps to generate-contracts
• e2e forked tests — Updated fork block numbers and whale addresses for new deployment

New Balances Deployment

Address 0x88b4B74082BffB2976C306CB3f7E9093AE48B94F on: Mainnet, Arbitrum, Base, Avalanche, BNB, Optimism, Polygon, Gnosis, Linea, Ink, Sepolia, Plasma. And also Optimism, since we deployed everything there already and in case we will add support for this chain sometime later.

Lens keeps the old address (0x3e8C6De9510e7ECad902D005DE3Ab52f35cF4f1b), since it will be dropped from the codebase in a follow-up PR.

Test plan

• Existing unit tests pass (account-balances, shared, orderbook)
• Clippy clean
• E2E local node tests pass
• E2E forked node tests pass
• Manual test: submit order with aToken that has LTV-blocked transfer, verify revert selector appears in error

[gemini-code-assist]

Code Review

This pull request enhances the balance simulation by capturing and propagating the revert reason when a transfer fails. Changes span the Solidity contract, generated bindings, and the backend validation logic. Feedback was provided regarding the error mapping in the order validator, where internal simulation errors are currently converted into client-side validation failures, potentially masking RPC or node issues and returning incorrect status codes.

[gemini-code-assist]

Mapping TransferSimulationError::Other to ValidationError::TransferSimulationFailed(Vec::new()) is potentially misleading. If the simulation failed due to an internal error (e.g., node connection issue, RPC failure), it should ideally be propagated as ValidationError::Other to trigger a 500 Internal Server Error instead of a 400 Bad Request. While this preserves existing behavior, the addition of the empty Vec highlights that we are losing the actual error context here.

Suggested change

	Err(ValidationError::TransferSimulationFailed(Vec::new()))
	Err(ValidationError::Other(err))

[gemini-code-assist]

Code Review

This pull request updates the Balances contract and simulation infrastructure to capture and return the revert reason when a transfer simulation fails. The changes involve Solidity contract updates, Rust binding regenerations, and API response modifications. Feedback was provided regarding the truncation of revert data in the API response; instead of providing only the first four bytes, the full revert data should be returned to enable clients to decode standard error strings and panic reasons.

[jmg-duarte]

LGTM

[MartinquaXD]

Good change! 👍