chore: rust-idiomatic compliance pass across M3 + M2 modules

crates/shepherd-sdk-test/Cargo.toml

@@ -7,7 +7,7 @@ repository.workspace = true
 description = "In-memory host mocks for Shepherd module unit tests. Implements shepherd_sdk::host::{ChainHost, LocalStoreHost, CowApiHost, LoggingHost}."
 
 [lib]
-# Plain library, host-only — module Cargo.toml lists this under
+# Plain library, host-only - module Cargo.toml lists this under
 # [dev-dependencies] so it never ships in the wasm bundle.
 
 [dependencies]

crates/shepherd-sdk-test/src/lib.rs

@@ -52,9 +52,10 @@
 //! The traits use [`shepherd_sdk::host::HostError`] rather than the
 //! `HostError` `wit_bindgen::generate!` emits per-module. A module
 //! bridges with two trivial `From` impls (one each direction) on its
-//! own crate boundary — see the M3 tutorial (BLEU-848) for the exact
+//! own crate boundary - see the M3 tutorial (BLEU-848) for the exact
 //! shape.
 
+#![cfg_attr(not(test), warn(unused_crate_dependencies))]
 #![warn(missing_docs)]
 
 use std::cell::RefCell;
@@ -213,7 +214,7 @@ impl MockLocalStore {
         self.rows.borrow().is_empty()
     }
 
-    /// Direct read for assertions — bypasses the trait.
+    /// Direct read for assertions - bypasses the trait.
     pub fn snapshot(&self) -> HashMap<String, Vec<u8>> {
         self.rows.borrow().clone()
     }

crates/shepherd-sdk/Cargo.toml

@@ -7,13 +7,13 @@ repository.workspace = true
 description = "Guest-side SDK for Shepherd modules: re-exports, helpers, and prelude on top of cowprotocol + alloy types."
 
 [lib]
-# Plain library — modules link this and emit their own cdylib for the
+# Plain library - modules link this and emit their own cdylib for the
 # WASM Component. Building shepherd-sdk on the host target is also
 # supported so the helpers are unit-testable without a wasm toolchain.
 
 [dependencies]
 cowprotocol = { version = "1.0.0-alpha.3", default-features = false }
 alloy-primitives = { version = "1.6", default-features = false, features = ["std", "serde"] }
 alloy-sol-types = { version = "1.5", default-features = false, features = ["std"] }
-serde = { version = "1", features = ["derive"] }
 serde_json = { version = "1", default-features = false, features = ["alloc"] }
+thiserror = "2"

crates/shepherd-sdk/README.md

@@ -19,7 +19,7 @@ use shepherd_sdk::chain::{eth_call_params, parse_eth_call_result};
 | Module | What it provides |
 |---|---|
 | `prelude` | One-liner `use ::*` for alloy primitives + cowprotocol order / signing / orderbook surface. |
-| `cow::order` | `gpv2_to_order_data` — `GPv2OrderData` -> typed `OrderData`. |
+| `cow::order` | `gpv2_to_order_data` - `GPv2OrderData` -> typed `OrderData`. |
 | `cow::composable` | `sol! IConditionalOrder` errors + `PollOutcome` + `decode_revert`. |
 | `cow::error` | `RetryAction` enum + `classify_api_error` + `try_decode_api_error`. |
 | `chain::eth_call` | `eth_call_params`, `parse_eth_call_result`, `decode_revert_hex`. |

crates/shepherd-sdk/src/cow/composable.rs

@@ -20,18 +20,18 @@ sol! {
     /// computed here match what the contract emits.
     #[derive(Debug)]
     interface IConditionalOrder {
-        /// `OrderNotValid(string)` — the order condition is permanently
+        /// `OrderNotValid(string)` - the order condition is permanently
         /// not met. Watch towers drop.
         error OrderNotValid(string reason);
-        /// `PollTryNextBlock(string)` — try again on the next block.
+        /// `PollTryNextBlock(string)` - try again on the next block.
         error PollTryNextBlock(string reason);
-        /// `PollTryAtBlock(uint256, string)` — try at or after the
+        /// `PollTryAtBlock(uint256, string)` - try at or after the
         /// given block number.
         error PollTryAtBlock(uint256 blockNumber, string reason);
-        /// `PollTryAtEpoch(uint256, string)` — try at or after the
+        /// `PollTryAtEpoch(uint256, string)` - try at or after the
         /// given Unix timestamp (seconds).
         error PollTryAtEpoch(uint256 timestamp, string reason);
-        /// `PollNever(string)` — the conditional order is dead.
+        /// `PollNever(string)` - the conditional order is dead.
         error PollNever(string reason);
     }
 }
@@ -40,7 +40,7 @@ sol! {
 /// `Ready` carries the materials the submit path needs; the other
 /// variants drive the lifecycle handler (BLEU-830).
 ///
-/// `Ready` is intentionally never produced by [`decode_revert`] — it
+/// `Ready` is intentionally never produced by [`decode_revert`] - it
 /// only comes from the successful return path the poll module
 /// constructs at the call site.
 #[derive(Debug)]
@@ -56,15 +56,15 @@ pub enum PollOutcome {
         /// orderbook prepends `from` before settlement).
         signature: Bytes,
     },
-    /// Retry on the very next block — typical for time-sliced TWAP
+    /// Retry on the very next block - typical for time-sliced TWAP
     /// schedules and other handlers that re-check on every tick.
     TryNextBlock,
     /// Retry once block number reaches the embedded value.
     TryOnBlock(u64),
     /// Retry once the wall clock (Unix seconds, UTC) reaches the
     /// embedded value.
     TryAtEpoch(u64),
-    /// Order is dead — drop the watch. Aggregates `OrderNotValid` and
+    /// Order is dead - drop the watch. Aggregates `OrderNotValid` and
     /// `PollNever` reverts; the original reason string is dropped
     /// because the lifecycle handler does not key off it today.
     DontTryAgain,
@@ -74,7 +74,7 @@ pub enum PollOutcome {
 /// [`PollOutcome`].
 ///
 /// Returns `None` when the selector is not one of the five
-/// [`IConditionalOrder`] errors — including a bare `Error(string)`
+/// [`IConditionalOrder`] errors - including a bare `Error(string)`
 /// require-revert. Callers should treat that as `TryNextBlock` (the
 /// safe default) so a transient RPC blip does not drop a still-valid
 /// watch.

crates/shepherd-sdk/src/cow/error.rs

@@ -4,7 +4,7 @@
 //! the lifecycle layer dispatches on. The orderbook returns a typed
 //! [`ApiError`] JSON body on permanent / transient failures; the host
 //! forwards that JSON in `host-error.data` (once the chain backend
-//! supports it — see the ADR follow-up). Until then,
+//! supports it - see the ADR follow-up). Until then,
 //! [`classify_api_error`] falls back to `TryNextBlock` so a flaky
 //! orderbook does not poison still-valid orders.
 //!
@@ -24,7 +24,7 @@ pub enum RetryAction {
     /// Leave the watch / placement in place; the next event will
     /// re-attempt.
     TryNextBlock,
-    /// Persist `next_attempt = now + seconds`. Reserved — no producer
+    /// Persist `next_attempt = now + seconds`. Reserved - no producer
     /// today (kept so the dispatch contract is stable).
     #[allow(dead_code)]
     Backoff {

crates/shepherd-sdk/src/cow/order.rs

@@ -19,7 +19,7 @@ use cowprotocol::{
 /// the wire as `bytes32` markers (the `keccak256` of the lowercase
 /// variant name). This helper hands them off to cowprotocol's
 /// `from_contract_bytes` classifiers and returns `None` when the on-
-/// chain payload carries a marker the SDK doesn't recognise — the
+/// chain payload carries a marker the SDK doesn't recognise - the
 /// caller skips the order rather than ship a malformed body.
 ///
 /// `receiver = Address::ZERO` is normalised to `None`; `OrderCreation::

crates/shepherd-sdk/src/host.rs

@@ -1,4 +1,4 @@
-//! Host traits — the seam between strategy logic and the wit-bindgen
+//! Host traits - the seam between strategy logic and the wit-bindgen
 //! shims a module generates per-cdylib.
 //!
 //! Each trait mirrors one nexum / shepherd host interface
@@ -13,7 +13,7 @@
 //!
 //! `wit_bindgen::generate!` emits a `HostError` struct into each
 //! module's own crate, so its identity is per-module. The SDK
-//! exposes [`HostError`] (this module) with the same field shape —
+//! exposes [`HostError`] (this module) with the same field shape  - 
 //! modules wire a one-liner `From` impl between the two so the
 //! traits stay world-neutral and the mocks compile without a wasm
 //! toolchain. See `shepherd-sdk-test`'s README for the adapter
@@ -29,9 +29,9 @@ pub enum LogLevel {
     Debug,
     /// Steady-state events.
     Info,
-    /// Recoverable errors — operator notice but no immediate action.
+    /// Recoverable errors - operator notice but no immediate action.
     Warn,
-    /// Unrecoverable errors — operator should investigate.
+    /// Unrecoverable errors - operator should investigate.
     Error,
 }
 
@@ -59,7 +59,8 @@ pub enum HostErrorKind {
 /// SDK-side counterpart to wit-bindgen's `HostError`. Same field shape
 /// so a module bridges between the two with a trivial `From` impl on
 /// each side.
-#[derive(Clone, Debug, Eq, PartialEq)]
+#[derive(Clone, Debug, Eq, PartialEq, thiserror::Error)]
+#[error("{domain}: {message} (code={code}, kind={kind:?})")]
 pub struct HostError {
     /// Short subsystem identifier (`"chain"`, `"local-store"`,
     /// `"cow-api"`, `"logging"`).
@@ -88,15 +89,15 @@ impl HostError {
     }
 }
 
-/// `nexum:host/chain` — raw JSON-RPC dispatch.
+/// `nexum:host/chain` - raw JSON-RPC dispatch.
 pub trait ChainHost {
     /// Execute a JSON-RPC request against the given chain. The host
     /// routes to its configured provider; the SDK does not care which
     /// transport (HTTP / WebSocket / mock) implements the call.
     fn request(&self, chain_id: u64, method: &str, params: &str) -> Result<String, HostError>;
 }
 
-/// `nexum:host/local-store` — per-module key-value persistence.
+/// `nexum:host/local-store` - per-module key-value persistence.
 pub trait LocalStoreHost {
     /// Fetch a value. `Ok(None)` when the key is absent.
     fn get(&self, key: &str) -> Result<Option<Vec<u8>>, HostError>;
@@ -108,14 +109,14 @@ pub trait LocalStoreHost {
     fn list_keys(&self, prefix: &str) -> Result<Vec<String>, HostError>;
 }
 
-/// `shepherd:cow/cow-api` — orderbook submission path.
+/// `shepherd:cow/cow-api` - orderbook submission path.
 pub trait CowApiHost {
     /// Submit an `OrderCreation` JSON body. The host returns the
     /// canonical order UID on success.
     fn submit_order(&self, chain_id: u64, body: &[u8]) -> Result<String, HostError>;
 }
 
-/// `nexum:host/logging` — structured runtime logs.
+/// `nexum:host/logging` - structured runtime logs.
 pub trait LoggingHost {
     /// Emit a log line at the given level.
     fn log(&self, level: LogLevel, message: &str);

crates/shepherd-sdk/src/lib.rs

@@ -9,30 +9,30 @@
 //!
 //! ## What lives here
 //!
-//! - [`prelude`] — `use shepherd_sdk::prelude::*` imports alloy
+//! - [`prelude`] - `use shepherd_sdk::prelude::*` imports alloy
 //!   primitives ([`Address`], [`B256`], [`Bytes`], [`U256`],
 //!   [`keccak256`]) and cowprotocol's order / signing / orderbook
 //!   surface ([`OrderCreation`], [`OrderData`], [`OrderUid`],
 //!   [`OrderKind`], [`Signature`], [`Chain`], [`GPv2OrderData`],
 //!   [`EMPTY_APP_DATA_JSON`], [`ApiError`], [`OrderPostErrorKind`]).
 //!
-//! - [`cow`] — `GPv2OrderData` -> `OrderData` bridging
+//! - [`cow`] - `GPv2OrderData` -> `OrderData` bridging
 //!   ([`gpv2_to_order_data`]), `IConditionalOrder` revert decoding
 //!   ([`PollOutcome`] + [`decode_revert`]), and the
 //!   [`RetryAction`] classifier driving submit-failure dispatch.
 //!
-//! - [`chain`] — `eth_call` JSON plumbing
+//! - [`chain`] - `eth_call` JSON plumbing
 //!   ([`eth_call_params`], [`parse_eth_call_result`],
 //!   [`decode_revert_hex`]).
 //!
-//! - [`host`] — host trait seam ([`Host`] / [`ChainHost`] /
+//! - [`host`] - host trait seam ([`Host`] / [`ChainHost`] /
 //!   [`LocalStoreHost`] / [`CowApiHost`] / [`LoggingHost`]) plus a
 //!   host-neutral [`HostError`]. Modules that want host-free tests
 //!   structure their strategy logic against these traits and slot
 //!   in the `shepherd-sdk-test` mocks. See the host module docs for
 //!   the wit-bindgen adapter pattern.
 //!
-//! - `store` — placeholder for `WatchSet` / `BackoffLedger`
+//! - `store` - placeholder for `WatchSet` / `BackoffLedger`
 //!   per ADR-0006. Populated when a second strategy module needs
 //!   the same key conventions.
 //!
@@ -44,7 +44,7 @@
 //! Helpers in this SDK therefore take primitive types (`&[u8]`,
 //! `Option<&str>`, slices) rather than the per-module `HostError`
 //! struct; modules unpack their `HostError` on the way in. Trade-off
-//! documented in ADR-0006 / ADR-0007 — the SDK stays on the guest
+//! documented in ADR-0006 / ADR-0007 - the SDK stays on the guest
 //! side, neutral to which world the module exports.
 //!
 //! [`Address`]: alloy_primitives::Address
@@ -76,6 +76,7 @@
 //! [`LoggingHost`]: host::LoggingHost
 //! [`HostError`]: host::HostError
 
+#![cfg_attr(not(test), warn(unused_crate_dependencies))]
 #![warn(missing_docs)]
 #![cfg_attr(docsrs, feature(doc_cfg))]
 
@@ -88,7 +89,7 @@ pub mod prelude;
 #[cfg(test)]
 mod tests {
     //! The skeleton has no behaviour to exercise; this test just
-    //! locks the prelude's surface — the build itself proves the
+    //! locks the prelude's surface - the build itself proves the
     //! re-exports compile against both `wasm32-wasip2` and the
     //! host target.
 

crates/shepherd-sdk/src/prelude.rs

@@ -32,7 +32,7 @@ pub use cowprotocol::{
     SigningScheme,
 };
 
-/// Re-exported `ApiError` typed error surface from the orderbook —
+/// Re-exported `ApiError` typed error surface from the orderbook  - 
 /// guest-side helpers (BLEU-840) read this back out of host-error JSON
 /// to drive the `RetryAction` dispatch.
 pub use cowprotocol::error::{ApiError, OrderPostErrorKind};