feat(composable): bindings for M2 contract mods (draft, depends on composable-cow PRs)

[brunota20]

Status: Draft. Depends on the four upstream composable-cow proposal PRs landing first. Once those PRs merge into bleu/composable-cow (or upstream cowprotocol/composable-cow), this PR's selectors / event signatures / struct field orders are locked against the canonical Solidity sources via the new tests; no further changes should be needed here.

What this adds

Additive Rust bindings + pure helpers for the four contract changes proposed in the composable-cow grant work. Every addition matches the existing cow-rs pattern: sol!-derived types + pure encode/decode helpers, no Provider plumbing — callers wrap their own RPC layer.

1. ConditionalOrderRegistered event

Added inside the existing ComposableCoW sol! interface block. Indexed owner / handler / ctx (= H(params)) lets watch towers filter at the RPC level with topics: [REGISTERED_HASH, null, handlerAddr]. The existing ConditionalOrderCreated topic-0 is untouched (no indexer breakage).

registered_topic_filter_by_handler(Address) -> [Option<B256>; 4] builds the four-slot filter array a caller passes to eth_subscribe logs.

2. batchGetTradeableOrdersWithSignature

BatchOrderRequest and BatchOrderResult struct bindings + the function selector. BatchOrderResult.order references crate::contracts::GPv2OrderData directly (sol! resolves the type across sibling blocks — confirmed by the existing OrderPlacement event reusing the same type).

decode_batch_order_result / decode_batch_order_results lower each result into a BatchOrderOutcome:

pub enum BatchOrderOutcome {
    Submitted { order: Box<GPv2OrderData>, signature: Bytes },
    PollHint(PollOutcome),
    ComposableCoWError(ComposableCoWError),
    UnknownRevert(Bytes),
}

GPv2OrderData is boxed inside Submitted to keep the enum compact (the order struct alone is ~320 bytes; clippy's large_enum_variant would otherwise fire, and the indirection is invisible to callers via auto-deref).

3. getOrderInfo combined accessor

OrderInfo struct binding (hash, authorized, cabinetValue, swapGuard) + function selector. Mirrors the on-chain helper that bundles four storage reads into one round trip.

4. IConditionalOrder error decoder

The five canonical errors from IConditionalOrder.sol (OrderNotValid, PollTryNextBlock, PollTryAtBlock, PollTryAtEpoch, PollNever) bound in a new sibling sol! interface, plus a decode_conditional_order_revert(&[u8]) -> Option<PollOutcome> decoder.

This is what unlocks TWAP's new behaviour from the polling-hints proposal: PollTryAtEpoch(t0, "before first part"), PollTryAtEpoch(nextPartStart, "between parts"), and PollNever("all parts settled") all decode out of the box. Tests assert each of the five errors round-trips through the decoder, with timestamp / blockNumber / reason arguments preserved byte-exact.

5. ComposableCoW *NotAuthed-style errors

Six errors (ProofNotAuthed, SingleOrderNotAuthed, SwapGuardRestricted, InvalidHandler, InvalidFallbackHandler, InterfaceNotSupported) bound in a sibling ComposableCoWErrors interface + decode_composable_cow_error(&[u8]) -> Option<ComposableCoWError> decoder. Cascades behind decode_conditional_order_revert inside decode_batch_order_result.

Files

• crates/cowprotocol-primitives/src/composable.rs — extended (events, structs, functions, decoders, helpers, tests)
• crates/cowprotocol-primitives/src/lib.rs — re-export additions
• crates/cowprotocol/src/lib.rs — re-export additions

Public surface added (all additive — no existing API changed)

pub enum PollOutcome { NotValid, TryNextBlock, TryAtBlock, TryAtEpoch, Never }
pub enum BatchOrderOutcome { Submitted, PollHint, ComposableCoWError, UnknownRevert }
pub enum ComposableCoWError { ProofNotAuthed, SingleOrderNotAuthed, ... }
pub fn decode_conditional_order_revert(data: &[u8]) -> Option<PollOutcome>
pub fn decode_composable_cow_error(data: &[u8]) -> Option<ComposableCoWError>
pub fn decode_batch_order_result(result: &ComposableCoW::BatchOrderResult) -> BatchOrderOutcome
pub fn decode_batch_order_results(results: &[ComposableCoW::BatchOrderResult]) -> Vec<BatchOrderOutcome>
pub fn registered_topic_filter_by_handler(handler: Address) -> [Option<B256>; 4]
// + sol!-generated types: IConditionalOrder, ComposableCoWErrors,
//   ComposableCoW::ConditionalOrderRegistered, ComposableCoW::BatchOrderRequest,
//   ComposableCoW::BatchOrderResult, ComposableCoW::OrderInfo,
//   ComposableCoW::batchGetTradeableOrdersWithSignatureCall,
//   ComposableCoW::getOrderInfoCall

Tests (16 new + 3 extended cases)

• conditional_order_registered_round_trips — event topic encoding
• registered_topic_filter_pins_handler_and_signature — filter helper
• batch_order_request_round_trips, batch_order_result_round_trips — ABI round-trips
• decode_batch_order_result_success, _poll_try_at_epoch, _composable_cow_error, _unknown_revert — outcome cascade
• decode_batch_order_results_preserves_order — order preservation across mixed batch
• order_info_round_trips, get_order_info_call_round_trips — getOrderInfo combined accessor
• decode_conditional_order_revert_covers_all_five_errors — all 5 IConditionalOrder errors + the three TWAP reverts byte-exact
• decode_conditional_order_revert_returns_none_for_unrelated_payloads — safety
• conditional_order_error_selectors_match_keccak, composable_cow_error_selectors_match_keccak — selector locks
• decode_composable_cow_error_covers_all_variants
• • 2 new selector cases in composable_cow_selectors_match_keccak (the two new view functions)
• • 1 new topic-hash case in composable_cow_event_topic_hashes_match_keccak

Gates

cargo fmt --all -- --check                                          OK
cargo clippy --all-targets --all-features --workspace -- -Dwarnings OK
cargo test --all-targets --all-features --workspace                 OK (289 passed, 0 failed)
cargo check --target wasm32-unknown-unknown --all-features          OK

Test plan

• Review the additive sol! surface against the canonical composable-cow PR sources once the upstream PRs settle to confirm field names, argument order, and selector strings.
• Once the contract PRs merge, retest against a Sepolia deployment with batchGetTradeableOrdersWithSignature returning a mixed batch (one success, one PollTryAtEpoch, one PollNever) and confirm decoding lines up.
• Confirm the ConditionalOrderRegistered topic filter delivers only the expected handler's events when subscribed via eth_subscribe logs on a live RPC.